CVE-2026-23274: Linux Kernel

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels IDLETIMER revision 0 rules reuse existing timers by label and always call mod_timer() on timer->timer. If the label was created first by revision 1 with XT_IDLETIMER_ALARM, the object uses alarm timer semantics and timer->timer is never initialized. Reusing that object from revision 0 causes mod_timer() on an uninitialized timer_list, triggering debugobjects warnings and possible panic when panic_on_warn=1. Fix this by rejecting revision 0 rule insertion when an existing timer with the same label is of ALARM type.

Affected products

• Linux Linux Kernel: from 5.7, before 5.10.253 (fixed in 5.10.253); from 5.11, before 5.15.203 (fixed in 5.15.203); from 5.16, before 6.1.167 (fixed in 6.1.167); from 6.2, before 6.6.130 (fixed in 6.6.130); from 6.7, before 6.12.78 (fixed in 6.12.78); from 6.13, before 6.18.19 (fixed in 6.18.19); …

Published 2026-03-20. Last modified 2026-07-14.