CVEvulnerability
CVE-2026-98490
9.8 CRITICAL
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)
- 9.8 CRITICAL — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Description
In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: conntrack: 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/18866dc1f525f9ee4de7709529d1ae1af8d8e8be git.kernel.org
- https://git.kernel.org/stable/c/1a4151e6be57b098b7a5ebfbde58585e83200cdc git.kernel.org
- https://git.kernel.org/stable/c/5f23080a625dd7855ab91485c8d691a54a1979f0 git.kernel.org
- https://git.kernel.org/stable/c/afcf362625190c5260530b1d6c7daa98831f6b83 git.kernel.org
- https://git.kernel.org/stable/c/e02a83bb0b7a203f6a22f55ad5f426765560f811 git.kernel.org