CVE-2026-23274

netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels

State: Published
Severity: 7.8 High
Published: Mar 20, 2026
Updated: Oct 19, 2026
Reserved: Jan 13, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

CWE-758 Reliance on Undefined, Unspecified, or Implementation-Defined Behavior

Affected Products

Product	Versions
LinuxLinux	68983a354a655c35d3fb204489d383a2a051fda7 to before 32e937dc6e97f5ed3cdfe3fc0b2b19a05e23fa44Affected 68983a354a655c35d3fb204489d383a2a051fda7 to before 144f88054ba0180467356f40895bd660b5dceeecAffected 68983a354a655c35d3fb204489d383a2a051fda7 to before 28c7cfaf0c0ab17cbd7754092116fd1af45271f9Affected 68983a354a655c35d3fb204489d383a2a051fda7 to before 54080355999381fed4a26129579a5765bab87491Affected 68983a354a655c35d3fb204489d383a2a051fda7 to before 5e7ece24c5cb75a60402aad4d803c7898ea40aa9Affected 68983a354a655c35d3fb204489d383a2a051fda7 to before f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1Affected 68983a354a655c35d3fb204489d383a2a051fda7 to before f228b9ae2a7e84d1153616d8e71c4236cb1f1309Affected 68983a354a655c35d3fb204489d383a2a051fda7 to before 329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cfAffected
LinuxLinux	5.7Affected before 5.7Not affected 5.10.253 through 5.10.Not affected 5.15.203 through 5.15.Not affected 6.1.167 through 6.1.Not affected 6.6.130 through 6.6.Not affected 6.12.78 through 6.12.Not affected 6.18.19 through 6.18.Not affected 6.19.9 through 6.19.*Not affected 7.0 and laterNot affected

Product

Versions

LinuxLinux

68983a354a655c35d3fb204489d383a2a051fda7 to before 32e937dc6e97f5ed3cdfe3fc0b2b19a05e23fa44Affected
68983a354a655c35d3fb204489d383a2a051fda7 to before 144f88054ba0180467356f40895bd660b5dceeecAffected
68983a354a655c35d3fb204489d383a2a051fda7 to before 28c7cfaf0c0ab17cbd7754092116fd1af45271f9Affected
68983a354a655c35d3fb204489d383a2a051fda7 to before 54080355999381fed4a26129579a5765bab87491Affected
68983a354a655c35d3fb204489d383a2a051fda7 to before 5e7ece24c5cb75a60402aad4d803c7898ea40aa9Affected
68983a354a655c35d3fb204489d383a2a051fda7 to before f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1Affected
68983a354a655c35d3fb204489d383a2a051fda7 to before f228b9ae2a7e84d1153616d8e71c4236cb1f1309Affected
68983a354a655c35d3fb204489d383a2a051fda7 to before 329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cfAffected

LinuxLinux

5.7Affected
before 5.7Not affected
5.10.253 through 5.10.*Not affected
5.15.203 through 5.15.*Not affected
6.1.167 through 6.1.*Not affected
6.6.130 through 6.6.*Not affected
6.12.78 through 6.12.*Not affected
6.18.19 through 6.18.*Not affected
6.19.9 through 6.19.*Not affected
7.0 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.