CVE-2026-9390
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk20th percentile - higher than 20% of all known CVEs
Summary
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.
Risk Assessment
An attacker can craft a URI to make the verification select different elements than intended, potentially bypassing signature integrity.
Recommendation
Upgrade XML::Sig to version 0.71 or later, which includes the fix.
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-2025-40934Critical
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.
- 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 before 0.71 for Perl allow XPath injection in ID lookup. verify() and _get_signed_xml() in lib/XML/Sig.pm build XPath expressions by concatenating the SignedInfo/Reference/@URI value read from the document being verified. The value is neither escaped nor checked against the NCName grammar that XML requires of an ID, so a URI containing a single quote closes the string literal in the generated expression and appends arbitrary XPath operators. A crafted URI can make the lookup match elements the reference does not name, or every element in the document, so which node is selected for digest verification is decided by the injected expression rather than by the reference.