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CVE-2026-64535

CRITICAL 9.8 ALL-YEARS

Published 2026-07-27 · Last modified 2026-10-19 · Linux · NVD: Received

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: Fix potential UAF when ddgst mismatch Shivam Kumar found via vulnerability testing: When data digest is enabled on an NVMe/TCP connection and a digest mismatch occurs on a non-final H2C_DATA PDU during an R2T-based data transfer, the digest error handler in nvmet_tcp_try_recv_ddgst() calls nvmet_req_uninit() — which performs percpu_ref_put() on the submission queue — but does NOT mark the command as completed. It does not set cqe->status, does not modify rbytes_done, and does not clear any flag. When the subsequent fatal error triggers queue teardown, nvmet_tcp_uninit_data_in_cmds() iterates all commands, checks nvmet_tcp_need_data_in() for each one, and finds that the already-uninited command still appears to need data (because rbytes_done < transfer_len and cqe->status == 0). It therefore calls nvmet_req_uninit() a second time on the same command — a double percpu_ref_put against a single percpu_ref_get.

ELEVATED IMPACT

Severe if exploited (CVSS 9.8), but no confirmed exploitation. Patch on a normal cadence.

Exploitation likelihood

0.5%chance of exploitation in 30 days · 46th percentile

○ In CISA KEV○ Catalogued PoC◆ SSVC: exploitation none, automatable yes

Impact if exploited

9.8CVSS 3.1 · CRITICAL · CNA

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓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.

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Affected

Vendors Linux

Products Linux

Weakness (CWE)

  • CWE-415: Double Free

CVSS vector

CVSS:3.1/AV:N/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 279 vendor product statements; 247 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: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-core as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-core

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+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: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-rt-debug as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-debug

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-uki-virt-addons as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-uki-virt-addons

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-modules-extra as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-modules-extra

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-rt-selftests-internal as a component of Red Hat Enterprise Linux 8 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-selftests-internal

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • bpftool as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/bpftool

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-64k-modules-core as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

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

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-debug-uki-virt as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-debug-uki-virt

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-rt-64k-debug as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

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

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-rt-64k-modules-internal as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

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

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-rt-modules as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-modules

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-zfcpdump-devel as a component of Red Hat Enterprise Linux 9 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-zfcpdump-devel

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · known affected

    Vendor assessment for this product only.

    pkg:oci/ose-rhel-coreos-9?repository_url=registry.redhat.io/openshift/ose-rhel-coreos-9

    • workaround: There is no mitigation for this issue other than applying the kernel update once available. Because Red Hat does not support and does not enable the nvmet-tcp target functionality by default, systems that have not been explicitly configured with nvmetcli to act as an NVMe-over-Fabrics TCP target are not exposed and require no immediate action. Administrators who have deliberately configured an NVMe/TCP target using this unsupported functionality should restrict network access to the target port to trusted initiators on the same storage network only, and should consider disabling NVMe/TCP data digest or migrating off nvmet-tcp given its unmaintained status, until the fix is applied.
    • none available: Fix deferred
    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • libkrun.src as a component of Red Hat Enterprise Linux 10 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/[email protected]?arch=src

    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-bootwrapper 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-bootwrapper

    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+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-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-firmware 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-firmware

    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-kdump-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-kdump-devel

    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • python-perf 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/python-perf

    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+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-2026-64535 · Updated 2026-10-12T16:37:25+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-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-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-doc

    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-kdump-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-kdump-devel

    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+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-2026-64535 · Updated 2026-10-12T16:37:25+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-2026-64535 · Updated 2026-10-12T16:37:25+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-2026-64535 · Updated 2026-10-12T16:37:25+00:00
  • kernel-rt.src 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?arch=src

    Red Hat · CVE-2026-64535 · Updated 2026-10-12T16:37:25+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-2026-64535 · Updated 2026-10-12T16:37:25+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-2026-64535 · Updated 2026-10-12T16:37:25+00:00

All CVSS metrics

  • CRITICAL 9.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • CRITICAL 9.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/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