# CVE-2026-53268: netfilter: conntrack_irc: fix possible out-of-bounds read

Status: published. Published: 2026-06-25. Updated: 2026-11-10.

In the Linux kernel, the following vulnerability has been resolved:

netfilter: conntrack_irc: fix possible out-of-bounds read

When parsing fails after we've matched the command string we
should bail out instead of trying to match a different command.

This helper should be deprecated, given prevalence of TLS I doubt it has
any relevance in 2026.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 869f37d8e48f3911eb70f38a994feaa8f8380008; < 4cdda7f868f48e2f81579371584fdbdce37df2c8 (affected, git); ≥ 869f37d8e48f3911eb70f38a994feaa8f8380008; < 8a1d6e40dedfe1068aee094d851bd69e289c9fd6 (affected, git); ≥ 869f37d8e48f3911eb70f38a994feaa8f8380008; < 0afc802160af0df61ed374fdb97fb34cfe5cdf2f (affected, git); ≥ 869f37d8e48f3911eb70f38a994feaa8f8380008; < 7c34f91305292083253df6a9f6c8ede02d4ccaea (affected, git); ≥ 869f37d8e48f3911eb70f38a994feaa8f8380008; < ddddd8271359961e403d11c90c9ba9fc38914f7e (affected, git); ≥ 869f37d8e48f3911eb70f38a994feaa8f8380008; < 9e5da2379f968a3ea5a6e38921ab6201576466dc (affected, git); ≥ 869f37d8e48f3911eb70f38a994feaa8f8380008; < 573810f61bcd6b6815e2ff53bbdd2b9c9d747176 (affected, git); ≥ 869f37d8e48f3911eb70f38a994feaa8f8380008; < 66eba0ffce3b7e11449946b4cbbef8ea36112f56 (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.20 (affected); ≥ 0; < 2.6.20 (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). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 TM MFP - GNU/Linux subsystem: ≥ 0; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CVSS 3.1: 8.2 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H; source: CNA: Linux

- CISA KEV: No listing in collected sources

- EPSS: 0.52% as of 2026-11-09; percentile 44.62%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-125

## Exploit evidence

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

## References

- https://git.kernel.org/stable/c/4cdda7f868f48e2f81579371584fdbdce37df2c8 (CNA: Linux)

- https://git.kernel.org/stable/c/8a1d6e40dedfe1068aee094d851bd69e289c9fd6 (CNA: Linux)

- https://git.kernel.org/stable/c/0afc802160af0df61ed374fdb97fb34cfe5cdf2f (CNA: Linux)

- https://git.kernel.org/stable/c/7c34f91305292083253df6a9f6c8ede02d4ccaea (CNA: Linux)

- https://git.kernel.org/stable/c/ddddd8271359961e403d11c90c9ba9fc38914f7e (CNA: Linux)

- https://git.kernel.org/stable/c/9e5da2379f968a3ea5a6e38921ab6201576466dc (CNA: Linux)

- https://git.kernel.org/stable/c/573810f61bcd6b6815e2ff53bbdd2b9c9d747176 (CNA: Linux)

- https://git.kernel.org/stable/c/66eba0ffce3b7e11449946b4cbbef8ea36112f56 (CNA: Linux)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-53268; retrieved 2026-11-10; source updated 2026-11-10

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-53268; retrieved 2026-11-10; source updated Not reported

Revision: b7bd169f9393bbe06add126c2623169ad6c554004d4aa710063513aa264791d1

Canonical: https://y2.dev/cve/CVE-2026-53268

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