CVE-2026-74492: Linux Vulnerability (CVSS 8.4)

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.

Metrics

CVSS 3.1

8.4/10

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.14%

4.0th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= f66ee0410b1c3481ee75e5db9b34547b4d582465, < 6f13f4d52d06986c18f12e8bffaab944dd27ceab; >= f66ee0410b1c3481ee75e5db9b34547b4d582465, < f9d6cabff1fca010562dcdb0d22b296bdca3ba5a; >= f66ee0410b1c3481ee75e5db9b34547b4d582465, < 16bfa7be2d76ca1e0aacfa363482e1bf8ab5042a; >= f66ee0410b1c3481ee75e5db9b34547b4d582465, < 661ff9c0cfbe07f8eed920dde9f7781491738207; >= f66ee0410b1c3481ee75e5db9b34547b4d582465, < c710e9bf38e4e71a8db85d26a0f70c0674664207; >= f66ee0410b1c3481ee75e5db9b34547b4d582465, < 4ae701848e4ba9e9713375fb7d82218cbd309da2; >= f66ee0410b1c3481ee75e5db9b34547b4d582465, < 77dbb248a5cc7a5270cd37bbb0b635bf059a872a; >= f66ee0410b1c3481ee75e5db9b34547b4d582465, < f30415929be8aeb002d557c8d3f7ab2d2188003a; 5dd9488ae41070b69d2f4acb580f77db5705f9ca; a469bab3386aebff33c59506f3a95e35b91118fd; >= 5.4.24, < 5.5; >= 5.5.8, < 5.6
Linux	Linux	5.6

References

Timeline

Published: Aug 15, 2026
Last Modified: Aug 19, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-74492?

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.

How severe is CVE-2026-74492?

CVE-2026-74492 has a CVSS score of 8.4/10 (HIGH severity). The EPSS model estimates a 0.14% probability of exploitation in the next 30 days.

How do I fix CVE-2026-74492?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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