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Fencer Vulns
high 7.1

CVE-2026-53223 json

net: guard timestamp cmsgs to real error queue skbs

published 2026-06-25 4 mo ago modified 2026-10-19 20 d ago also EUVD-2026-39314

cvss
7.1
version 3.1, CNA
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: guard timestamp cmsgs to real error queue skbs

skb_is_err_queue() treats PACKET_OUTGOING as the sole marker for an skb from sk_error_queue. That assumption is not true for AF_PACKET sockets: outgoing packet taps are also delivered to packet sockets with skb->pkt_type == PACKET_OUTGOING, but their skb->cb is owned by AF_PACKET instead of struct sock_exterr_skb.

If such an skb is received with timestamping enabled, the generic timestamp cmsg path can read AF_PACKET control-buffer state as sock_exterr_skb::opt_stats. With SO_RXQ_OVFL enabled, the packet drop counter overlaps opt_stats. An odd drop count makes the path emit SCM_TIMESTAMPING_OPT_STATS with skb->len and skb->data. For non-linear skbs this copies past the linear head and can trigger hardened usercopy or disclose adjacent heap contents.

Keep skb_is_err_queue() local to net/socket.c, but make it verify that the PACKET_OUTGOING marker is paired with the sock_rmem_free destructor installed by sock_queue_err_skb(). AF_PACKET receive skbs use normal receive ownership and no longer pass as error-queue skbs, while legitimate sk_error_queue entries keep the PACKET_OUTGOING marker and sock_rmem_free ownership.

Patch / fix

  • Linux Linux 4.11, 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36, 7.0.13, 7.1
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.94-1
  • linux Debian 14 7.0.13-1

debian advisories DEBIAN-CVE-2026-53223

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 24.04 LTS 6.8.0-146.146
  • linux Ubuntu 26.04 LTS 7.0.0-31.31
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1066.69
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1012.12
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1070.78

ubuntu advisories UBUNTU-CVE-2026-53223

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 8 4.18.0-553.164.1.el8_10
  • perf RHEL 8 4.18.0-553.164.1.el8_10
  • bpftool RHEL 8 4.18.0-553.164.1.el8_10
  • kernel-core RHEL 8 4.18.0-553.164.1.el8_10
  • kernel-tools RHEL 8 4.18.0-553.164.1.el8_10
  • python3-perf RHEL 8 4.18.0-553.164.1.el8_10
  • kernel-modules RHEL 8 4.18.0-553.164.1.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.164.1.el8_10

red hat advisories RHSA-2026:68531RHSA-2026:68532RHSA-2026:66180RHSA-2026:64775

  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.81.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.81.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1
  • kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.81.1
  • kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.81.1.150700.17.45.1

suse advisories SUSE-SU-2026:4254-1SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1SUSE-SU-2026:4282-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1

  • kernel AlmaLinux 8 4.18.0-553.164.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.164.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.164.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.164.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.164.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.164.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.164.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.164.1.el8_10

almalinux advisories ALSA-2026:68531ALSA-2026:68532ALSA-2026:66180

  • kernel-rt Rocky Linux 8 4.18.0-553.164.1.rt7.505.el8_10
  • kernel Rocky Linux 8 4.18.0-553.164.1.el8_10
  • kernel Rocky Linux 9 5.14.0-687.46.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.52.1.el10_2

rocky linux advisories RLSA-2026:68532RLSA-2026:68531RLSA-2026:66180RLSA-2026:64775

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-2026-53223 updated cvss 7.0

kernel: net: guard timestamp cmsgs to real error queue skbs

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 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
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.46.1.el9_8, perf 5.14.0-687.46.1.el9_8, rtla 5.14.0-687.46.1.el9_8, python3-perf 5.14.0-687.46.1.el9_8, kernel-devel-matched 5.14.0-687.46.1.el9_8, kernel-64k-devel-matched 5.14.0-687.46.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:66180
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.52.1.el10_2, perf 6.12.0-211.52.1.el10_2, rtla 6.12.0-211.52.1.el10_2, python3-perf 6.12.0-211.52.1.el10_2, kernel-devel-matched 6.12.0-211.52.1.el10_2, kernel-64k-devel-matched 6.12.0-211.52.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:64775
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.164.1.el8_10, kernel 4.18.0-553.164.1.el8_10, bpftool 4.18.0-553.164.1.el8_10, kernel-core 4.18.0-553.164.1.el8_10, kernel-tools 4.18.0-553.164.1.el8_10, python3-perf 4.18.0-553.164.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:68531
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.46.1.el9_8, kernel-64k 5.14.0-687.46.1.el9_8, kernel-core 5.14.0-687.46.1.el9_8, kernel-tools 5.14.0-687.46.1.el9_8, kernel-modules 5.14.0-687.46.1.el9_8, kernel-64k-core 5.14.0-687.46.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:66180
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.52.1.el10_2, kernel-64k 6.12.0-211.52.1.el10_2, kernel-core 6.12.0-211.52.1.el10_2, kernel-tools 6.12.0-211.52.1.el10_2, kernel-modules 6.12.0-211.52.1.el10_2, kernel-64k-core 6.12.0-211.52.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:64775
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.46.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.46.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.46.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.46.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.46.1.el9_8
    fixed: vendor fix RHSA-2026:66180
show 8 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.52.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.52.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.52.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.52.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.52.1.el10_2
    fixed: vendor fix RHSA-2026:64775
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.164.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.164.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.164.1.el8_10
    fixed: vendor fix RHSA-2026:68531
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-kvm 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-core 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-modules 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-debug-kvm 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-debug-core 4.18.0-553.164.1.rt7.505.el8_10, +4 more
    fixed: vendor fix RHSA-2026:68532
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.46.1.el9_8, kernel-rt-64k 5.14.0-687.46.1.el9_8, kernel-rt-core 5.14.0-687.46.1.el9_8, kernel-rt-modules 5.14.0-687.46.1.el9_8, kernel-rt-64k-core 5.14.0-687.46.1.el9_8, kernel-rt-debug-core 5.14.0-687.46.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:66180
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.52.1.el10_2, kernel-rt-64k 6.12.0-211.52.1.el10_2, kernel-rt-core 6.12.0-211.52.1.el10_2, kernel-rt-modules 6.12.0-211.52.1.el10_2, kernel-rt-64k-core 6.12.0-211.52.1.el10_2, kernel-rt-debug-core 6.12.0-211.52.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:64775
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.46.1.el9_8, kernel-rt-core 5.14.0-687.46.1.el9_8, kernel-rt-modules 5.14.0-687.46.1.el9_8, kernel-rt-debug-core 5.14.0-687.46.1.el9_8, kernel-rt-modules-core 5.14.0-687.46.1.el9_8, kernel-rt-debug-modules 5.14.0-687.46.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:66180
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.52.1.el10_2, kernel-rt-core 6.12.0-211.52.1.el10_2, kernel-rt-modules 6.12.0-211.52.1.el10_2, kernel-rt-debug-core 6.12.0-211.52.1.el10_2, kernel-rt-modules-core 6.12.0-211.52.1.el10_2, kernel-rt-debug-modules 6.12.0-211.52.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:64775
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-core 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-modules 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-debug-core 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-debug-modules 4.18.0-553.164.1.rt7.505.el8_10, kernel-rt-modules-extra 4.18.0-553.164.1.rt7.505.el8_10, +2 more
    fixed: vendor fix RHSA-2026:68532

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 7.1

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 SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
23 d ago

Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.1 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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
Technology feeds

References

Sources

Fencer Vulns 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.