CVE-2026-98442

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

HIGH
7.8
CVSS Score
Published: October 18, 2026 at 03:14 PM UTC
Updated: October 24, 2026 at 02:16 PM UTC
1 product affected across 1 vendorLinux Kernel

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Severity
HIGH7.8
Exploit prediction
EPSS 0.1%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

6.2a21b06e7319129994f339ed47f512bbe57b77f5b
Vendor states this is fixed in 6.12.112 (unaffected)
Vendor states this is fixed in 6.18.55 (unaffected)
Vendor states this is fixed in 6.6.160 (unaffected)
Vendor states this is fixed in 7.2.9 (unaffected)
Vendor states this is fixed in 7.3 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

7.8HIGHLinux
Vector?

Quick Info

StatusRECEIVED

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