CVE-2026-56404

publishedCWE-190

libexpat before 2.8.2 has an integer overflow in addBinding.

Technical severity6.9 mediumCVSS 3.1 · CNA: mitre

Published2026-06-21Source updated 2026-11-10

Collected2026-11-102 attributed sources

Fixes and workarounds

No remediation reported in collected sources.

Missing remediation information is not evidence that no patch exists.

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
libexpat libexpat project	≥ 0; < 2.8.2 (affected, semver) Other versions: unaffected	CNA: mitre
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	≥ V3.1.7; < * (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	≥ V3.1.7; < * (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.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 6.9 medium	`CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L`	CNA: mitre

Exploit evidence

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

References

https://github.com/libexpat/libexpat/pull/1249CNA: mitre
https://cert-portal.siemens.com/productcert/html/ssa-457936.htmlADP: siemens-SADP

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