Answer in brief
CVE-2026-53269 records a Medium severity (CVSS 5.5) vulnerability in netfilter: synproxy: add mutex to guard hook reference counting. 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 1518F-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 5.5. 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 1518F-4 PN/DP MFP (generic) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=ad49d86e07a497e834cb06f2b151dccd75f8e148 <0ec9ddc1bda261a2c57636c74c8b4e53000102c9 || >=ad49d86e07a497e834cb06f2b151dccd75f8e148 <56ffbe3a08c01dcdb0d6adee9ce1e535bfb3b389 || >=ad49d86e07a497e834cb06f2b151dccd75f8e148 <debc57b83d5b323df74bf010c8d50fe26ad2ed6b || >=ad49d86e07a497e834cb06f2b151dccd75f8e148 <0f8ba5e4c53d2e4a536aa68140beda9fe59b2f88 || >=ad49d86e07a497e834cb06f2b151dccd75f8e148 <640441348258220e78daed40528b85b8afcedab6 || >=ad49d86e07a497e834cb06f2b151dccd75f8e148 <aaf80701dc2f7a48fe543961e21f8ca3924d587c || >=ad49d86e07a497e834cb06f2b151dccd75f8e148 <fbf0591275f50eae5733c3d7a8cd6c1e79933ffa || >=ad49d86e07a497e834cb06f2b151dccd75f8e148 <2fcba19caaeb2a33017459d3430f057967bb91b6 | 0ec9ddc1bda261a2c57636c74c8b4e53000102c9, 56ffbe3a08c01dcdb0d6adee9ce1e535bfb3b389, debc57b83d5b323df74bf010c8d50fe26ad2ed6b, 0f8ba5e4c53d2e4a536aa68140beda9fe59b2f88, 640441348258220e78daed40528b85b8afcedab6, aaf80701dc2f7a48fe543961e21f8ca3924d587c, fbf0591275f50eae5733c3d7a8cd6c1e79933ffa, 2fcba19caaeb2a33017459d3430f057967bb91b6 |
| Linux/Linuxgeneric | 5.3 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
Published upstream
Jun 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
Jun 25, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: add mutex to guard hook reference counting As the synproxy infrastructure register netfilter hooks on-demand when a user adds the first iptables target or nftables expression, if done concurrently they can race each other. Introduce a mutex to serialize the refcount control blocks access from both frontends. While a per namespace mutex might be more efficient, it is not needed for target/expression like SYNPROXY.
Quoted source text, attributed separately from HOL analysis.