CVE-2026-9487
XML::Sig versions before 0.71 for Perl allow signature wrapping via duplicate ID
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.
INFO
Published Date :
Aug. 3, 2026, 2:16 p.m.
Last Modified :
Aug. 5, 2026, 2:57 p.m.
Remotely Exploit :
Yes !
Source :
9b29abf9-4ab0-4765-b253-1875cd9b441e
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update the XML::Sig library to version 0.71 or later.
- Ensure proper handling of duplicate IDs in XML documents.
- Validate XML signatures carefully to prevent attacks.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-9487.
| URL | Resource |
|---|---|
| https://github.com/perl-net-saml2/perl-XML-Sig/commit/4976bde5245df69b8e02c6ae061acbd4891cd7f9.patch | Patch |
| https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/source/Changes | Release Notes |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-9487 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-9487
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-9487 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-9487 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Aug. 05, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:xml::sig_project:xml::sig:*:*:*:*:*:perl:*:* versions up to (excluding) 0.71 Added Reference Type CPANSec: https://github.com/perl-net-saml2/perl-XML-Sig/commit/4976bde5245df69b8e02c6ae061acbd4891cd7f9.patch Types: Patch Added Reference Type CPANSec: https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/source/Changes Types: Release Notes -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 03, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Added SSVC {'id': 'CVE-2026-9487', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-03T19:59:25.051641Z'} -
New CVE Received by 9b29abf9-4ab0-4765-b253-1875cd9b441e
Aug. 03, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/perl-net-saml2/perl-XML-Sig', 'vendor': 'TIMLEGGE', 'product': 'XML::Sig', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.71', 'versionType': 'custom'}], 'packageName': 'XML-Sig', 'programFiles': ['lib/XML/Sig.pm'], 'collectionURL': 'https://cpan.org/modules', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'XML::Sig::verify'}, {'name': 'XML::Sig::_get_signed_xml'}]}] 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. Added CWE CWE-347 Added Reference https://github.com/perl-net-saml2/perl-XML-Sig/commit/4976bde5245df69b8e02c6ae061acbd4891cd7f9.patch Added Reference https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/source/Changes