Vulnpedia
← All CVEs

CVE-2026-74540

HIGH 8.8 ALL-YEARS

Published 2026-08-15 · Last modified 2026-10-16 · Linux · NVD: Received

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix UAF in l2cap_le_connect_rsp l2cap_le_connect_rsp() obtains a channel via __l2cap_get_chan_by_ident() but neither holds a reference nor uses l2cap_chan_hold_unless_zero() before locking and operating on it. A concurrent l2cap_chan_del() triggered by a remote disconnect can free the channel between the lookup and l2cap_chan_lock(), causing a use-after-free. The BR/EDR counterpart l2cap_connect_rsp() and the sibling handler l2cap_le_command_rej() already use l2cap_chan_hold_unless_zero() to safely hold a reference, but l2cap_le_connect_rsp() was left unprotected. Fix by adding l2cap_chan_hold_unless_zero() after the ident lookup and l2cap_chan_put() on the exit path, consistent with other L2CAP response handlers.

ELEVATED IMPACT

Severe if exploited (CVSS 8.8), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.3%chance of exploitation in 30 days · 17th percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable no

Impact if exploited

8.8CVSS 3.1 · HIGH · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ⚠Access: Must sit on the same / adjacent network
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked weekly for the full archive, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Affected

Vendors Linux

Products Linux

Weakness (CWE)

Not classified.

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References and research data (JSON)

Vendor product assessments

Showing 32 of 275 vendor product statements; 243 omitted. Read the full vendor advisory.

  • kernel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-abi-stablelists as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-abi-stablelists

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-modules-extra-matched as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-modules-extra-matched

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt-core as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-core

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-uki-virt as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-uki-virt

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • bpftool as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/bpftool

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-modules as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-modules

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt-modules-extra as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-modules-extra

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • python3-perf as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/python3-perf

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-64k-devel-matched as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-64k-devel-matched

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-debug-modules-internal as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-debug-modules-internal

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt-64k as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-64k

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt-64k-modules-core as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-64k-modules-core

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt-devel as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-devel

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-zfcpdump as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-zfcpdump

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • rv as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/rv

    • workaround: The flaw is reachable only through the Bluetooth stack, so it can be mitigated by disabling Bluetooth on systems that do not require it: stop and disable the bluetooth service (systemctl disable --now bluetooth), block the Bluetooth radio with rfkill block bluetooth, or disable Bluetooth in the system firmware. Restricting physical proximity of untrusted Bluetooth peers also limits the attack surface, since the flaw requires an attacker within Bluetooth radio range. For environments where Bluetooth must remain enabled, mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
    • none available: Fix deferred
    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-debug as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-debug

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-devel as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-devel

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-headers as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-headers

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel.src as a component of Red Hat Enterprise Linux 6 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel?arch=src

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • bpftool as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/bpftool

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-abi-whitelists as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-abi-whitelists

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-debug-devel as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-debug-devel

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-headers as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-headers

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt-debug-devel as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt-debug-devel

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt-doc as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt-doc

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-rt-trace-devel as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-rt-trace-devel

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-tools as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-tools

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • kernel-tools-libs-devel as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-tools-libs-devel

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00
  • python-perf as a component of Red Hat Enterprise Linux 7 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/python-perf

    Red Hat · CVE-2026-74540 · Updated 2026-10-17T21:25:18+00:00

All CVSS metrics

  • HIGH 8.8 v3.1 · CNA Primary
    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • HIGH 8.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Advisories

Technical & other

Sources: NVD · CVE.org · All sources and attribution · EPSS