CVEvulnerability
CVE-2026-98442
7.8 HIGH
Official page ↗
- Status
- Received
- Published
- 2026-10-18
- Last modified
- 2026-10-24
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- CVSS 3.1 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)
- 7.8 HIGH — CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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.
References
- https://git.kernel.org/stable/c/1679bbf5fbeac52a310b1a58b2b301bbf388bdbf git.kernel.org
- https://git.kernel.org/stable/c/31f5fe29a572037ee19c233dfe506849940c484b git.kernel.org
- https://git.kernel.org/stable/c/812c16a255e7773a544e88b39ae6daed25544d30 git.kernel.org
- https://git.kernel.org/stable/c/8988f4d11f3fba0ab38122178836c683ad516a05 git.kernel.org
- https://git.kernel.org/stable/c/dad19b59da050cb60d3f7023dac2a042a84bf0bd git.kernel.org