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Fencer Intel
high 7.8

CVE-2026-98442 json

net/sched: act_ct: fix helper UAF due to extensions realloc

published 24d ago modified 18d ago also EUVD-2026-103682

cvss
7.8
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 2%
public exploits
0
none known

Summary

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

net/sched: act_ct: fix helper UAF due to extensions realloc

While calling the helpers, a raw pointer to the extensions area is wired into expectations list:

-> nf_ct_helper() -> helper->help() -> nf_ct_expect_related_report() -> nf_ct_expect_insert() -> hlist_add_head_rcu(&exp->lnode, &master_help->expectations)

In case the connection is not confirmed yet, more extensions can be added afterwards with *_ext_add() calls reallocating the extension space and leaving the now invalid pointer in the expectations list that is later accessed while removing the expectation.

Make sure that helpers are called at the end after all the other extensions are already added.

Note that the helper rejection now leaves the mark and labels set, but that's not different from how the NAT was handled before or how the mark and the labels were handled on confirmation failure. And there are no atomicity guarantees provided by the API anyway.

Patch / fix

  • Linux Linux 7.3
  • linux Debian 13 6.12.113-1
  • linux Debian 14 7.2.9-1
  • linux-6.12 Debian 12 6.12.113-1~deb12u1

debian advisories DEBIAN-CVE-2026-98442

  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-ibm Ubuntu 26.04 LTS 7.0.0-1017.17
  • linux-riscv Ubuntu 26.04 LTS 7.0.0-42.42.1
  • linux-oracle Ubuntu 26.04 LTS 7.0.0-1015.16
  • linux-hwe-7.0 Ubuntu 24.04 LTS 7.0.0-42.42~24.04.1
  • linux-oem-7.0 Ubuntu 26.04 LTS 7.0.0-1017.17

ubuntu advisories UBUNTU-CVE-2026-98442

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 Azure Linux 3.0 6.6.161.1-1

azure linux advisories AZL-108806

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

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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-2026-98442 updated cvss 7.5

kernel: net/sched: act_ct: fix helper UAF due to extensions realloc

  • 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 Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-741.22.1.el9_9, perf 5.14.0-741.22.1.el9_9, rtla 5.14.0-741.22.1.el9_9, python3-perf 5.14.0-741.22.1.el9_9, kernel-devel-matched 5.14.0-741.22.1.el9_9, kernel-64k-devel-matched 5.14.0-741.22.1.el9_9, +7 more Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-741.22.1.el9_9, kernel-64k 5.14.0-741.22.1.el9_9, kernel-core 5.14.0-741.22.1.el9_9, kernel-tools 5.14.0-741.22.1.el9_9, kernel-modules 5.14.0-741.22.1.el9_9, kernel-64k-core 5.14.0-741.22.1.el9_9, +27 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-741.22.1.el9_9, kernel-debuginfo-common-s390x 5.14.0-741.22.1.el9_9, kernel-debuginfo-common-x86_64 5.14.0-741.22.1.el9_9, kernel-debuginfo-common-aarch64 5.14.0-741.22.1.el9_9, kernel-debuginfo-common-ppc64le 5.14.0-741.22.1.el9_9 Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-741.22.1.el9_9, kernel-rt-64k 5.14.0-741.22.1.el9_9, kernel-rt-core 5.14.0-741.22.1.el9_9, kernel-rt-modules 5.14.0-741.22.1.el9_9, kernel-rt-64k-core 5.14.0-741.22.1.el9_9, kernel-rt-debug-core 5.14.0-741.22.1.el9_9, +14 more Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-741.22.1.el9_9, kernel-rt-core 5.14.0-741.22.1.el9_9, kernel-rt-modules 5.14.0-741.22.1.el9_9, kernel-rt-debug-core 5.14.0-741.22.1.el9_9, kernel-rt-modules-core 5.14.0-741.22.1.el9_9, kernel-rt-debug-modules 5.14.0-741.22.1.el9_9, +5 more
    fixed: vendor fix RHSA-2026:99135
  • 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 OpenShift Container Platform 4 openshift/ose-rhel-coreos-8
    not affected: vulnerable code not present

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

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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