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Fencer Vulns
critical 9.8

CVE-2026-74569 in the critical feed json

netfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp()

published 2026-08-15 2 mo ago modified 2026-10-16 23 d ago also EUVD-2026-59634

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

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

netfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp()

sip_help_tcp() stores the size change of each NAT-rewritten SIP message in s16 diff and accumulates it in s16 tdiff, but a single message can grow by more than S16_MAX while the packet stays under the 65535 enlarge_skb() limit: nf_nat_sip() rewrites every matching URI, and a long Contact list expands the message by tens of kilobytes. diff then wraps, and "datalen = datalen + diff - msglen" yields a huge unsigned datalen, so the next iteration's ct_sip_get_header() reads past the linearized skb tail.

Widen diff, tdiff and the seq_adjust hook to s32. Both are bounded by the 65535 byte packet limit, and the seqadj core is already s32 (nf_ct_seqadj_set() takes s32), so no previously accepted input is rejected.

BUG: KASAN: use-after-free in ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464) Read of size 1 at addr ffff888010800000 by task ksoftirqd/1/25 ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464) sip_help_tcp (net/netfilter/nf_conntrack_sip.c:1694) nf_confirm (net/netfilter/nf_conntrack_proto.c:183) nf_hook_slow (net/netfilter/core.c:619) ip6_output (net/ipv6/ip6_output.c:246) ip6_forward (net/ipv6/ip6_output.c:690) ipv6_rcv (net/ipv6/ip6_input.c:351) __netif_receive_skb_one_core (net/core/dev.c:6212) process_backlog (net/core/dev.c:6676) __napi_poll (net/core/dev.c:7735) net_rx_action (net/core/dev.c:7955) handle_softirqs (kernel/softirq.c:622) run_ksoftirqd (kernel/softirq.c:1076) ...

Patch / fix

  • Linux Linux 5.10.265, 5.15.216, 6.1.183, 6.6.151, 6.12.103, 6.18.44, 7.1.8, 7.2
  • linux Debian 12 6.1.187-1
  • linux Debian 13 6.12.105-1
  • linux Debian 14 7.1.8-1
  • linux-6.12 Debian 12 6.12.107-1~deb12u1

debian advisories DEBIAN-CVE-2026-74569

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1113.119
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1111.115

ubuntu advisories UBUNTU-CVE-2026-74569

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 5.14.0-687.55.1.el9_8
  • rv RHEL 9 5.14.0-687.55.1.el9_8
  • perf RHEL 9 5.14.0-687.55.1.el9_8
  • rtla RHEL 9 5.14.0-687.55.1.el9_8
  • libperf RHEL 9 5.14.0-687.55.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.55.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.55.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.55.1.el9_8

red hat advisories RHSA-2026:76739RHSA-2026:75747RHSA-2026:75746RHSA-2026:71233

  • kernel-rt AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-core AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-modules AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-debug-core AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-debug-modules-extra AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel AlmaLinux 8 4.18.0-553.171.1.el8_10

almalinux advisories ALSA-2026:75746ALSA-2026:75747ALSA-2026:71233

  • kernel-rt Rocky Linux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel Rocky Linux 8 4.18.0-553.171.1.el8_10

rocky linux advisories RLSA-2026:75746RLSA-2026:75747

  • kernel Azure Linux 3.0 6.6.152.1-1

azure linux advisories AZL-96003

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-74569 updated cvss 7.0

kernel: netfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp()

  • 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 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    under investigation
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.55.1.el9_8, perf 5.14.0-687.55.1.el9_8, rtla 5.14.0-687.55.1.el9_8, python3-perf 5.14.0-687.55.1.el9_8, kernel-devel-matched 5.14.0-687.55.1.el9_8, kernel-64k-devel-matched 5.14.0-687.55.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.59.1.el10_2, perf 6.12.0-211.59.1.el10_2, rtla 6.12.0-211.59.1.el10_2, python3-perf 6.12.0-211.59.1.el10_2, kernel-devel-matched 6.12.0-211.59.1.el10_2, kernel-64k-devel-matched 6.12.0-211.59.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:71233
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.171.1.el8_10, kernel 4.18.0-553.171.1.el8_10, bpftool 4.18.0-553.171.1.el8_10, kernel-core 4.18.0-553.171.1.el8_10, kernel-tools 4.18.0-553.171.1.el8_10, python3-perf 4.18.0-553.171.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:75747
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.55.1.el9_8, kernel-64k 5.14.0-687.55.1.el9_8, kernel-core 5.14.0-687.55.1.el9_8, kernel-tools 5.14.0-687.55.1.el9_8, kernel-modules 5.14.0-687.55.1.el9_8, kernel-64k-core 5.14.0-687.55.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.59.1.el10_2, kernel-64k 6.12.0-211.59.1.el10_2, kernel-core 6.12.0-211.59.1.el10_2, kernel-tools 6.12.0-211.59.1.el10_2, kernel-modules 6.12.0-211.59.1.el10_2, kernel-64k-core 6.12.0-211.59.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:71233
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.55.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.55.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.55.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.55.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.55.1.el9_8
    fixed: vendor fix RHSA-2026:76739
show 8 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.59.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.59.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.59.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.59.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.59.1.el10_2
    fixed: vendor fix RHSA-2026:71233
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.171.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.171.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.171.1.el8_10
    fixed: vendor fix RHSA-2026:75747
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-kvm 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-core 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-modules 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-kvm 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-core 4.18.0-553.171.1.rt7.512.el8_10, +4 more
    fixed: vendor fix RHSA-2026:75746
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.55.1.el9_8, kernel-rt-64k 5.14.0-687.55.1.el9_8, kernel-rt-core 5.14.0-687.55.1.el9_8, kernel-rt-modules 5.14.0-687.55.1.el9_8, kernel-rt-64k-core 5.14.0-687.55.1.el9_8, kernel-rt-debug-core 5.14.0-687.55.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.59.1.el10_2, kernel-rt-64k 6.12.0-211.59.1.el10_2, kernel-rt-core 6.12.0-211.59.1.el10_2, kernel-rt-modules 6.12.0-211.59.1.el10_2, kernel-rt-64k-core 6.12.0-211.59.1.el10_2, kernel-rt-debug-core 6.12.0-211.59.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:71233
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.55.1.el9_8, kernel-rt-core 5.14.0-687.55.1.el9_8, kernel-rt-modules 5.14.0-687.55.1.el9_8, kernel-rt-debug-core 5.14.0-687.55.1.el9_8, kernel-rt-modules-core 5.14.0-687.55.1.el9_8, kernel-rt-debug-modules 5.14.0-687.55.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.59.1.el10_2, kernel-rt-core 6.12.0-211.59.1.el10_2, kernel-rt-modules 6.12.0-211.59.1.el10_2, kernel-rt-debug-core 6.12.0-211.59.1.el10_2, kernel-rt-modules-core 6.12.0-211.59.1.el10_2, kernel-rt-debug-modules 6.12.0-211.59.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:71233
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-core 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-modules 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-core 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-modules 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-modules-extra 4.18.0-553.171.1.rt7.512.el8_10, +2 more
    fixed: vendor fix RHSA-2026:75746

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 SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

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.