Insufficient verification of data authenticity in XMLSecLibs - #VU145062
Published: August 25, 2026
Vulnerability identifier: #VU145062
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-345
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to forge signatures.
The vulnerability exists due to insufficient verification of data authenticity in verify() and locateKey() when verifying signed XML documents with a caller-supplied key. A remote attacker can supply a crafted signature that downgrades the signature method to hmac-sha1 to forge signatures.
The issue arises because the document\'s SignatureMethod was not always bound to the algorithm of the caller-supplied key, allowing RSA public key material to be treated as an HMAC secret.
Affected software
XMLSecLibs
Remediation
Install security update from vendor's website.
XMLSecLibs - update to 4.0.0