CVE-2025-40934
CriticalSummary
XML-Sig versions 0.27 through 0.67 for Perl incorrectly validates XML files if signatures are omitted. An attacker can remove the signature from an XML document to make it pass verification. XML-Sig is a Perl module to validate signatures on XML files. An unsigned XML file should return an error, but affected versions return true when validating an XML file with no signatures.
Risk Assessment
An attacker could forge XML documents by removing signatures, potentially leading to data integrity and authorization bypass in systems using XML-Sig.
Recommendation
Update XML-Sig to a version later than 0.67. If possible, enforce the presence of signatures in processed XML documents.
Other vulnerabilities in XML-Sig
See all- CVE-2026-9487Critical
A vulnerability in the XML::Sig library for Perl (versions before 0.71) allows signature wrapping via duplicate ID. The _get_signed_xml() function selects the first node from the XPath result set, enabling an attacker to substitute the content of a signed document.
- CVE-2026-9390Critical
XPath injection vulnerability in XML::Sig for Perl before version 0.71. The verify() and _get_signed_xml() functions build XPath expressions without proper escaping of the URI value from the document, allowing injection of arbitrary XPath operators.
- CVE-2026-18568High
XML::Sig for Perl versions 0.29 through 0.71 allow signature verification bypass. The verify function returns true when every signature was skipped before any cryptographic check. An attacker can supply an XML document with two Signature elements whose URI references a non-existent ID, causing verify to return true without checking the signature.
Original NVD description (English source)
XML-Sig versions 0.27 through 0.67 for Perl incorrectly validates XML files if signatures are omitted. An attacker can remove the signature from the XML document to make it pass the verification check. XML-Sig is a Perl module to validate signatures on XML files. An unsigned XML file should return an error message. The affected versions return true when attempting to validate an XML file that contains no signatures.