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CVE-2026-74492

netfilter: ipset: do not update comments from kernel-side hash adds

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.5, 5.6, 5.10.265, 5.15.216, 6.1.183, and 4 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: total

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: total

  3. Record last updated

Affected versions

  • Linux Linux

    From f66ee0410b1c3481ee75e5db9b34547b4d582465 · fixed in 6f13f4d52d06986c18f12e8bffaab944dd27ceab; From f66ee0410b1c3481ee75e5db9b34547b4d582465 · fixed in f9d6cabff1fca010562dcdb0d22b296bdca3ba5a; From f66ee0410b1c3481ee75e5db9b34547b4d582465 · fixed in 16bfa7be2d76ca1e0aacfa363482e1bf8ab5042a; From f66ee0410b1c3481ee75e5db9b34547b4d582465 · fixed in 661ff9c0cfbe07f8eed920dde9f7781491738207; From f66ee0410b1c3481ee75e5db9b34547b4d582465 · fixed in c710e9bf38e4e71a8db85d26a0f70c0674664207; From f66ee0410b1c3481ee75e5db9b34547b4d582465 · fixed in 4ae701848e4ba9e9713375fb7d82218cbd309da2; From f66ee0410b1c3481ee75e5db9b34547b4d582465 · fixed in 77dbb248a5cc7a5270cd37bbb0b635bf059a872a; From f66ee0410b1c3481ee75e5db9b34547b4d582465 · fixed in f30415929be8aeb002d557c8d3f7ab2d2188003a; From 5.4.24 · fixed in 5.5; From 5.5.8 · fixed in 5.6

  • Linux Linux

    5.6

  • KernelLinux

    From 5.6.0 · fixed in 5.10.265; From 5.11.0 · fixed in 5.15.216; From 5.16.0 · fixed in 6.1.183; From 6.2.0 · fixed in 6.6.151; From 6.7.0 · fixed in 6.12.103; From 6.13.0 · fixed in 6.18.44; From 6.19.0 · fixed in 7.1.8

References 8

git.kernel.org