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CVE-2026-53269

netfilter: synproxy: add mutex to guard hook reference counting

published

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.

Technical severity5.5 mediumCVSS 3.1 · NVD: [email protected]

Published2026-06-25Source updated 2026-11-10

Collected2026-11-103 attributed sources

Fixes and workarounds

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
Linux Linux	≥ ad49d86e07a497e834cb06f2b151dccd75f8e148; < 0ec9ddc1bda261a2c57636c74c8b4e53000102c9 (affected, git) ≥ ad49d86e07a497e834cb06f2b151dccd75f8e148; < 56ffbe3a08c01dcdb0d6adee9ce1e535bfb3b389 (affected, git) ≥ ad49d86e07a497e834cb06f2b151dccd75f8e148; < debc57b83d5b323df74bf010c8d50fe26ad2ed6b (affected, git) ≥ ad49d86e07a497e834cb06f2b151dccd75f8e148; < 0f8ba5e4c53d2e4a536aa68140beda9fe59b2f88 (affected, git) ≥ ad49d86e07a497e834cb06f2b151dccd75f8e148; < 640441348258220e78daed40528b85b8afcedab6 (affected, git) ≥ ad49d86e07a497e834cb06f2b151dccd75f8e148; < aaf80701dc2f7a48fe543961e21f8ca3924d587c (affected, git) ≥ ad49d86e07a497e834cb06f2b151dccd75f8e148; < fbf0591275f50eae5733c3d7a8cd6c1e79933ffa (affected, git) ≥ ad49d86e07a497e834cb06f2b151dccd75f8e148; < 2fcba19caaeb2a33017459d3430f057967bb91b6 (affected, git) Other versions: unaffected	CNA: Linux
Linux Linux	5.3 (affected) ≥ 0; < 5.3 (unaffected, semver) ≥ 5.10.259; ≤ 5.10.* (unaffected, semver) ≥ 5.15.210; ≤ 5.15.* (unaffected, semver) ≥ 6.1.176; ≤ 6.1.* (unaffected, semver) ≥ 6.6.143; ≤ 6.6.* (unaffected, semver) ≥ 6.12.94; ≤ 6.12.* (unaffected, semver) ≥ 6.18.36; ≤ 6.18.* (unaffected, semver) ≥ 7.0.13; ≤ 7.0.* (unaffected, semver) ≥ 7.1; ≤ * (unaffected, original_commit_for_fix) Other versions: affected	CNA: Linux
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIMATIC S7-1500 TM MFP - GNU/Linux subsystem Siemens	≥ 0; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) Siemens	≥ V3.1.6; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) Siemens	≥ V3.1.7; < * (affected, custom) Other versions: unknown	ADP: siemens-SADP

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

NVD applicability configurations (1)

These expressions retain AND/OR operators, negation, and required environmental products. A listed product is not sufficient to establish exposure when additional conditions apply.

[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "5.10.259",
            "versionStartIncluding": "5.3",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "5.15.210",
            "versionStartIncluding": "5.11",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.1.176",
            "versionStartIncluding": "5.16",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.6.143",
            "versionStartIncluding": "6.2",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.12.94",
            "versionStartIncluding": "6.7",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.18.36",
            "versionStartIncluding": "6.13",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "7.0.13",
            "versionStartIncluding": "6.19",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 5.5 medium	`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`	NVD: [email protected]

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://git.kernel.org/stable/c/0ec9ddc1bda261a2c57636c74c8b4e53000102c9CNA: Linux
https://git.kernel.org/stable/c/56ffbe3a08c01dcdb0d6adee9ce1e535bfb3b389CNA: Linux
https://git.kernel.org/stable/c/debc57b83d5b323df74bf010c8d50fe26ad2ed6bCNA: Linux
https://git.kernel.org/stable/c/0f8ba5e4c53d2e4a536aa68140beda9fe59b2f88CNA: Linux
https://git.kernel.org/stable/c/640441348258220e78daed40528b85b8afcedab6CNA: Linux
https://git.kernel.org/stable/c/aaf80701dc2f7a48fe543961e21f8ca3924d587cCNA: Linux
https://git.kernel.org/stable/c/fbf0591275f50eae5733c3d7a8cd6c1e79933ffaCNA: Linux
https://git.kernel.org/stable/c/2fcba19caaeb2a33017459d3430f057967bb91b6CNA: Linux
https://cert-portal.siemens.com/productcert/html/ssa-019113.htmlADP: siemens-SADP
https://cert-portal.siemens.com/productcert/html/ssa-457936.htmlADP: siemens-SADP
https://cert-portal.siemens.com/productcert/html/ssa-784472.htmlADP: siemens-SADP
https://git.kernel.org/stable/c/0ec9ddc1bda261a2c57636c74c8b4e53000102c9416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/0f8ba5e4c53d2e4a536aa68140beda9fe59b2f88416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/2fcba19caaeb2a33017459d3430f057967bb91b6416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/56ffbe3a08c01dcdb0d6adee9ce1e535bfb3b389416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/640441348258220e78daed40528b85b8afcedab6416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/aaf80701dc2f7a48fe543961e21f8ca3924d587c416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/debc57b83d5b323df74bf010c8d50fe26ad2ed6b416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://git.kernel.org/stable/c/fbf0591275f50eae5733c3d7a8cd6c1e79933ffa416baaa9-dc9f-4396-8d5f-8c081fb06d67 · Patch
https://cert-portal.siemens.com/productcert/html/ssa-019113.html0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
https://cert-portal.siemens.com/productcert/html/ssa-457936.html0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
https://cert-portal.siemens.com/productcert/html/ssa-784472.html0b142b55-0307-4c5a-b3c9-f314f3fb7c5e

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