Answer in brief
CVE-2026-23391 records a High severity (CVSS 7.8) vulnerability in netfilter: xt_CT: drop pending enqueued packets on template removal. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=24de58f465165298aaa8f286b2592f0163706cfe <55445134d42b84cb0a272e42c98d233ca65eca83 || >=24de58f465165298aaa8f286b2592f0163706cfe <cc57506dd66555899560b9c0f24e813f034e12ec || >=24de58f465165298aaa8f286b2592f0163706cfe <d2d0bae0c9a2a17b6990a2966f5cdce0813d6256 || >=24de58f465165298aaa8f286b2592f0163706cfe <63b8097cea1923fe82cd598068d0796da8c015ec || >=24de58f465165298aaa8f286b2592f0163706cfe <19a230dec6bb8928e3f96387f9085cf2c79bcef9 || >=24de58f465165298aaa8f286b2592f0163706cfe <cb549925875fa06dd155e49db4ac2c5044c30f9c || >=24de58f465165298aaa8f286b2592f0163706cfe <777d02efe3d630cca4c1b63962cec17c57711325 || >=24de58f465165298aaa8f286b2592f0163706cfe <f62a218a946b19bb59abdd5361da85fa4606b96b | 55445134d42b84cb0a272e42c98d233ca65eca83, cc57506dd66555899560b9c0f24e813f034e12ec, d2d0bae0c9a2a17b6990a2966f5cdce0813d6256, 63b8097cea1923fe82cd598068d0796da8c015ec, 19a230dec6bb8928e3f96387f9085cf2c79bcef9, cb549925875fa06dd155e49db4ac2c5044c30f9c, 777d02efe3d630cca4c1b63962cec17c57711325, f62a218a946b19bb59abdd5361da85fa4606b96b |
| Linux/Linuxgeneric | 3.4 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.5 <* | * |
Published upstream
Mar 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 14, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_CT: drop pending enqueued packets on template removal Templates refer to objects that can go away while packets are sitting in nfqueue refer to: - helper, this can be an issue on module removal. - timeout policy, nfnetlink_cttimeout might remove it. The use of templates with zone and event cache filter are safe, since this just copies values. Flush these enqueued packets in case the template rule gets removed.
Quoted source text, attributed separately from HOL analysis.