High 7.8Published Mar 20, 2026

CVE-2026-23274netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels

Updated under an hour ago (Oct 27, 2026, 4:50 AM ET)

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Exploited in the last 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.

CVSS: 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-758
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: Oct 19, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	68983a354a655c35d3fb204489d383a2a051fda7 builds before 32e937dc6e97f5ed3cdfe3fc0b2b19a05e23fa44; 68983a354a655c35d3fb204489d383a2a051fda7 builds before 144f88054ba0180467356f40895bd660b5dceeec; 68983a354a655c35d3fb204489d383a2a051fda7 builds before 28c7cfaf0c0ab17cbd7754092116fd1af45271f9; from 68983a354a655c35d3fb204489d383a2a051fda7 before 54080355999381fed4a26129579a5765bab87491; 68983a354a655c35d3fb204489d383a2a051fda7 builds before 5e7ece24c5cb75a60402aad4d803c7898ea40aa9; from 68983a354a655c35d3fb204489d383a2a051fda7 before f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1; from 68983a354a655c35d3fb204489d383a2a051fda7 before f228b9ae2a7e84d1153616d8e71c4236cb1f1309; 68983a354a655c35d3fb204489d383a2a051fda7 builds before 329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cf	CNA record
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP siemens:simatic_s7_1500_cpu_1518f_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name)	all versions	CISA ADP
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP siemens:siplus_s7_1500_cpu_1518_4_pn_dp_mfp (from the name)	from V3.1.6	CISA ADP
linux linux_kernel linux:linux_kernel	from 5.7 before 5.10.253; from 5.11 before 5.15.203; from 5.16 before 6.1.167; from 6.2 before 6.6.130; from 6.7 before 6.12.78; from 6.13 before 6.18.19; from 6.19 before 6.19.9; 7.0; and 2 more ranges	NVD

References

References

https://git.kernel.org/stable/c/32e937dc6e97f5ed3cdfe3fc0b2b19a05e23fa44	patch
https://git.kernel.org/stable/c/144f88054ba0180467356f40895bd660b5dceeec	patch
https://git.kernel.org/stable/c/28c7cfaf0c0ab17cbd7754092116fd1af45271f9	patch
https://git.kernel.org/stable/c/54080355999381fed4a26129579a5765bab87491	patch
https://git.kernel.org/stable/c/5e7ece24c5cb75a60402aad4d803c7898ea40aa9	patch
https://git.kernel.org/stable/c/f5ef97c13165542480a6ffdbe6f09f40bbb7cbf1	patch
https://git.kernel.org/stable/c/f228b9ae2a7e84d1153616d8e71c4236cb1f1309	patch
https://git.kernel.org/stable/c/329f0b9b48ee6ab59d1ab72fef55fe8c6463a6cf	patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html
https://cert-portal.siemens.com/productcert/html/ssa-082556.html
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.