CVE-2026-53269

netfilter: synproxy: add mutex to guard hook reference counting

MEDIUM
5.5
CVSS Score
Published: June 25, 2026 at 08:39 AM UTC
Updated: October 15, 2026 at 02:20 AM UTC
4 products affected across 2 vendorsLinux KernelSIMATIC S7-1500 CPU 1518-4 Pn /dp MFP FirmwareSiplus S7-1500 CPU 1518-4 Pn /dp MFP Firmware

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Severity
MEDIUM5.5
Exploit prediction
EPSS 0.1%

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

5.11 ≤ v < 5.15.2105.16 ≤ v < 6.1.1765.3 ≤ v < 5.10.2596.13 ≤ v < 6.18.366.19 ≤ v < 7.0.136.2 ≤ v < 6.6.1436.7 ≤ v < 6.12.947.17.1 rc17.1 rc27.1 rc37.1 rc47.1 rc57.1 rc6ad49d86e07a497e834cb06f2b151dccd75f8e148
Vendor states this is fixed in 0ec9ddc1bda261a2c57636c74c8b4e53000102c9 (fixed)
Vendor states this is fixed in 0f8ba5e4c53d2e4a536aa68140beda9fe59b2f88 (fixed)
Vendor states this is fixed in 2fcba19caaeb2a33017459d3430f057967bb91b6 (fixed)
Vendor states this is fixed in 56ffbe3a08c01dcdb0d6adee9ce1e535bfb3b389 (fixed)
Vendor states this is fixed in 640441348258220e78daed40528b85b8afcedab6 (fixed)
Vendor states this is fixed in aaf80701dc2f7a48fe543961e21f8ca3924d587c (fixed)
Vendor states this is fixed in debc57b83d5b323df74bf010c8d50fe26ad2ed6b (fixed)
Vendor states this is fixed in fbf0591275f50eae5733c3d7a8cd6c1e79933ffa (fixed)
Vendor states this is fixed in 5.10.259 (unaffected)
Vendor states this is fixed in 5.15.210 (unaffected)
Vendor states this is fixed in 5.3 (unaffected)
Vendor states this is fixed in 6.1.176 (unaffected)
Vendor states this is fixed in 6.12.94 (unaffected)
Vendor states this is fixed in 6.18.36 (unaffected)
Vendor states this is fixed in 6.6.143 (unaffected)
Vendor states this is fixed in 7.0.13 (unaffected)
Vendor states this is fixed in 7.1 (unaffected)

CVSS

Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
NVD-CWE-noinfo

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