Vulnerability · Published Aug 3, 2026 · Assigned by CPANSec
CVE-2026-9487XML::Sig versions before 0.71 for Perl allow signature wrapping via duplicate ID
Critical 9.1
In plain English
A critical-severity security flaw in XML::Sig from TIMLEGGE. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N