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CVE-2026-98239

HIGH 8.1

Published 2026-10-06 · Last modified 2026-10-19

In the Linux kernel, the following vulnerability has been resolved: net: lan743x: fix RX checksum use-after-free lan743x_rx_process_buffer() adds each non-first receive buffer to the head skb's frag_list. On the last descriptor, lan743x_rx_trim_skb() linearizes the head and frees the fragment skb metadata. The checksum-success path then writes ip_summed through the local skb pointer, which still points to the final fragment. This causes a use-after-free write when a packet spans more than one receive buffer. Set ip_summed on the surviving head skb instead. Multi-buffer receive can occur after a live MTU increase because existing ring entries keep their old buffer size until they are replenished. A KUnit test invoking lan743x_rx_process_buffer() with a two-buffer packet produced a one-byte KASAN use-after-free write before this change. The same test passed after the change. The driver object also builds with W=1. This was not tested on physical LAN743x hardware.

ELEVATED IMPACT

Severe if exploited (CVSS 8.1), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.4%chance of exploitation in 30 days · 38th percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

8.1CVSS 3.1 · HIGH

  • 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: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

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

Data snapshot:

Affected

Vendors Linux

Products Linux

Weakness (CWE)

Not classified.

CVSS vector

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

References and research data (JSON)

Vendor product assessments

Showing 32 of 277 vendor product statements; 245 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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-64k-debug-devel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-64k-devel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-debug-devel-matched as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-devel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-devel

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-modules-extra as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-modules-extra

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-rt-64k-core as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-rt-64k-debug-modules-extra as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-rt-debug-modules as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-rt-modules as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-rt-modules

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-tools-libs-devel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

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

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-zfcpdump-devel as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel-zfcpdump-devel

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel.src as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/kernel?arch=src

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • rv as a component of Red Hat Enterprise Linux 10 · known affected

    Vendor assessment for this product only.

    pkg:rpm/redhat/rv

    • none available: Affected
    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+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-2026-98239 · Updated 2026-10-09T07:19:15+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-2026-98239 · Updated 2026-10-09T07:19:15+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-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • 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/perf

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-debug-modules-internal as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-rt-debug-kvm as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-tools-libs-devel as a component of Red Hat Enterprise Linux 8 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-64k-core as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-64k-modules-core as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-debug-modules-extra as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-modules-partner as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-modules-partner

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-rt-64k-debug-modules-partner as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-rt-debug-devel-matched as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-rt-modules-internal as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • kernel-zfcpdump-modules as a component of Red Hat Enterprise Linux 9 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    pkg:rpm/redhat/kernel-zfcpdump-modules

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00
  • openshift/ose-rhel-coreos-9 as a component of Red Hat OpenShift Container Platform 4 · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

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

    Red Hat · CVE-2026-98239 · Updated 2026-10-09T07:19:15+00:00

All CVSS metrics

  • HIGH 8.1 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
  • HIGH 8.1 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS