PT-2026-67421 · Timlegge · Xml::Sig

CVE-2026-9487 · Published 2026-08-03 · Updated 2026-08-03

NVD

CVSS v3.1

9.1

Critical

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

XML::Sig versions before 0.71 for Perl allow signature wrapping via duplicate ID.

get signed xml() in lib/XML/Sig.pm, called from verify(), resolves the SignedInfo Reference/@URI to a node with the XPath expression "//*[@ID='$id']" and returns the first node of the resulting node set. A document in which two elements share that ID value is accepted: the digest and signature are checked against whichever element comes first in document order, and the duplicate is not detected.

Such a document verifies successfully while an application that resolves the same ID independently can read the second, attacker supplied element; in a SAML2 context this places the contents of an Assertion under attacker control.

Fix

Improper Verification of Cryptographic Signature

Weakness Enumeration

CWE-347

Related Identifiers

CVE-2026-9487

Affected Products

Xml::Sig

References · 3

• https://github.com/perl-net-saml2/perl-XML-Sig/commit/4976bde5245df69b8e02c6ae061acbd4891cd7f9.patch · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-9487 · Security Note
• https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/source/Changes · Note