CVE-2026-74492
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: do not update comments from kernel-side hash adds mtype_resize() copies comment pointers with memcpy(), not the comment objects themselves. During the window after an entry has been copied but before the table swap and backlog replay, the old table is still published for packet-side updates while the replacement-table entry already holds the same ip_set_comment_rcu pointer. If xt_SET --add-set ... --exist hits that old entry in this window, mtype_add() calls ip_set_init_comment() even though packet-side adds carry no comment payload. That call frees the shared comment through the old entry, so the replacement-table entry now holds a stale pointer. When the queued add is replayed on the new table, mtype_add() calls ip_set_init_comment() again and strlen() dereferences the stale pointer. Fix this in mtype_add() by skipping ip_set_init_comment() when ext->target marks a packet-side add. Userspace adds still update comments, while packet-side adds can no longer free comment storage shared with a resize copy.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
Propose a mitigation on Community Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
References
- https://git.kernel.org/stable/c/4ae701848e4ba9e9713375fb7d82218cbd309da2
- https://git.kernel.org/stable/c/661ff9c0cfbe07f8eed920dde9f7781491738207
- https://git.kernel.org/stable/c/77dbb248a5cc7a5270cd37bbb0b635bf059a872a
- https://git.kernel.org/stable/c/c710e9bf38e4e71a8db85d26a0f70c0674664207
- https://git.kernel.org/stable/c/f30415929be8aeb002d557c8d3f7ab2d2188003a
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.