Vulnerability in Timlegge Xml::sig

CVE-2026-9487

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.

EPSS: 0.002 (6.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-9487?
CVE-2026-9487 is a critical-severity vulnerability in Timlegge Xml::sig, classified under Improper Verification of Cryptographic Signature. CVSS score: 9.1/10. Published 2026-08-03.
How severe is CVE-2026-9487?
Critical severity. CVSS v3 base score is 9.1 out of 10.