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Fencer Intel
medium 5.5

CVE-2026-22979 json

net: fix memory leak in skb_segment_list for GRO packets

published 9mo ago modified 4d ago also EUVD-2026-4307

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

net: fix memory leak in skb_segment_list for GRO packets

When skb_segment_list() is called during packet forwarding, it handles packets that were aggregated by the GRO engine.

Historically, the segmentation logic in skb_segment_list assumes that individual segments are split from a parent SKB and may need to carry their own socket memory accounting. Accordingly, the code transfers truesize from the parent to the newly created segments.

Prior to commit ed4cccef64c1 ("gro: fix ownership transfer"), this truesize subtraction in skb_segment_list() was valid because fragments still carry a reference to the original socket.

However, commit ed4cccef64c1 ("gro: fix ownership transfer") changed this behavior by ensuring that fraglist entries are explicitly orphaned (skb->sk = NULL) to prevent illegal orphaning later in the stack. This change meant that the entire socket memory charge remained with the head SKB, but the corresponding accounting logic in skb_segment_list() was never updated.

As a result, the current code unconditionally adds each fragment's truesize to delta_truesize and subtracts it from the parent SKB. Since the fragments are no longer charged to the socket, this subtraction results in an effective under-count of memory when the head is freed. This causes sk_wmem_alloc to remain non-zero, preventing socket destruction and leading to a persistent memory leak.

The leak can be observed via KMEMLEAK when tearing down the networking environment:

unreferenced object 0xffff8881e6eb9100 (size 2048): comm "ping", pid 6720, jiffies 4295492526 backtrace: kmem_cache_alloc_noprof+0x5c6/0x800 sk_prot_alloc+0x5b/0x220 sk_alloc+0x35/0xa00 inet6_create.part.0+0x303/0x10d0 __sock_create+0x248/0x640 __sys_socket+0x11b/0x1d0

Since skb_segment_list() is exclusively used for SKB_GSO_FRAGLIST packets constructed by GRO, the truesize adjustment is removed.

The call to skb_release_head_state() must be preserved. As documented in commit cf673ed0e057 ("net: fix fraglist segmentation reference count leak"), it is still required to correctly drop references to SKB extensions that may be overwritten during __copy_skb_header().

Patch / fix

  • Linux Linux 5.16, 6.1.161, 6.6.121, 6.9, 6.12.66, 6.18.6, 6.19
  • linux Debian 12 6.1.162-1
  • linux Debian 13 6.12.69-1
  • linux Debian 14 6.18.8-1

debian advisories DEBIAN-CVE-2026-22979

  • linux Ubuntu 24.04 LTS 6.8.0-117.117
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1055.58
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1058.61
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1054.60
  • linux-ibm Ubuntu 24.04 LTS 6.8.0-1055.56
  • linux-azure Ubuntu 24.04 LTS 6.8.0-1056.62
  • linux-gkeop Ubuntu 24.04 LTS 6.8.0-1041.44
  • linux-raspi Ubuntu 24.04 LTS 6.8.0-1056.60

ubuntu advisories UBUNTU-CVE-2026-22979

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 9 5.14.0-687.25.1.el9_8
  • rv RHEL 9 5.14.0-687.25.1.el9_8
  • perf RHEL 9 5.14.0-687.25.1.el9_8
  • rtla RHEL 9 5.14.0-687.25.1.el9_8
  • libperf RHEL 9 5.14.0-687.25.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.25.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.25.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.25.1.el9_8

red hat advisories RHSA-2026:38491

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.34.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.34.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.34.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.34.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.34.1.150700.17.23.1

suse advisories SUSE-SU-2026:1081-1SUSE-SU-2026:20873-1SUSE-SU-2026:20838-1SUSE-SU-2026:20931-1SUSE-SU-2026:20845-1SUSE-SU-2026:20876-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.27.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.27.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.27.1

opensuse advisories openSUSE-SU-2026:20416-1

  • kernel AlmaLinux 9 5.14.0-687.25.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.25.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.25.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.25.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.25.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.25.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.25.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.25.1.el9_8

almalinux advisories ALSA-2026:38491

  • kernel Rocky Linux 9 5.14.0-687.25.1.el9_8

rocky linux advisories RLSA-2026:38491

Is CVE-2026-22979 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-22979 updated cvss 5.5

kernel: Linux kernel: Memory leak in networking due to incorrect GRO packet handling

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more Red Hat Enterprise Linux 10 kernel
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.25.1.el9_8, perf 5.14.0-687.25.1.el9_8, rtla 5.14.0-687.25.1.el9_8, python3-perf 5.14.0-687.25.1.el9_8, kernel-devel-matched 5.14.0-687.25.1.el9_8, kernel-64k-devel-matched 5.14.0-687.25.1.el9_8, +7 more Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.25.1.el9_8, kernel-64k 5.14.0-687.25.1.el9_8, kernel-core 5.14.0-687.25.1.el9_8, kernel-tools 5.14.0-687.25.1.el9_8, kernel-modules 5.14.0-687.25.1.el9_8, kernel-64k-core 5.14.0-687.25.1.el9_8, +27 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.25.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.25.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.25.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.25.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.25.1.el9_8 Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.25.1.el9_8, kernel-rt-64k 5.14.0-687.25.1.el9_8, kernel-rt-core 5.14.0-687.25.1.el9_8, kernel-rt-modules 5.14.0-687.25.1.el9_8, kernel-rt-64k-core 5.14.0-687.25.1.el9_8, kernel-rt-debug-core 5.14.0-687.25.1.el9_8, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.25.1.el9_8, kernel-rt-core 5.14.0-687.25.1.el9_8, kernel-rt-modules 5.14.0-687.25.1.el9_8, kernel-rt-debug-core 5.14.0-687.25.1.el9_8, kernel-rt-modules-core 5.14.0-687.25.1.el9_8, kernel-rt-debug-modules 5.14.0-687.25.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:38491

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-26-295-11 updated cvss 5.5

Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.7 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.7
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-26-209-04 updated cvss 5.5

Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.6 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.6
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
4d ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.