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.
Published: 2026-08-03
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Solution

Upgrade to version 0.71


Vendor Workaround

Signing the outermost <samlp:Response> element rather than only the inner <saml:Assertion> reduces exposure, but does not prevent wrapping variants in which the duplicate ID is introduced outside the signed element. Upgrading to 0.71 is the complete fix.

Tracking

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Advisories

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History

Mon, 03 Aug 2026 16:15:00 +0000

Type Values Removed Values Added
First Time appeared Timlegge
Timlegge xml::sig
Vendors & Products Timlegge
Timlegge xml::sig

Mon, 03 Aug 2026 13:45:00 +0000

Type Values Removed Values Added
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.
Title XML::Sig versions before 0.71 for Perl allow signature wrapping via duplicate ID
Weaknesses CWE-347
References

Subscriptions

Timlegge Xml::sig
cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-08-03T13:14:43.135Z

Reserved: 2026-05-24T13:47:37.954Z

Link: CVE-2026-9487

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-03T15:51:30Z

Weaknesses
  • CWE-347

    Improper Verification of Cryptographic Signature