CVE-2026-9390
XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup
Description
XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup. verify() and _get_signed_xml() in lib/XML/Sig.pm build XPath expressions by concatenating the SignedInfo/Reference/@URI value read from the document being verified. The value is neither escaped nor checked against the NCName grammar that XML requires of an ID, so a URI containing a single quote closes the string literal in the generated expression and appends arbitrary XPath operators. A crafted URI can make the lookup match elements the reference does not name, or every element in the document, so which node is selected for digest verification is decided by the injected expression rather than by the reference.
INFO
Published Date :
Aug. 3, 2026, 2:16 p.m.
Last Modified :
Oct. 23, 2026, 9:10 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 XML::Sig to version 0.71 or later.
- Sanitize or validate input for URI attributes.
- Avoid concatenating untrusted data in XPath expressions.
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-2026-9390.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-9390 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-2026-9390
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-2026-9390 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-9390 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.
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CVE Translated by [email protected]
Oct. 23, 2026
Action Type Old Value New Value Added Translation Title: XML::Sig de TIMLEGGE, Description: Las versiones de XML::Sig anteriores a la 0.71 para Perl permiten la inyección de XPath en la búsqueda de ID. verify() y _get_signed_xml() en lib/XML/Sig.pm construyen expresiones XPath concatenando el valor SignedInfo/Reference/@URI leído del documento que se está verificando. El valor no se escapa ni se verifica contra la gramática NCName que XML requiere para un ID, por lo que un URI que contiene una comilla simple cierra el literal de cadena en la expresión generada y añade operadores XPath arbitrarios. Un URI manipulado puede hacer que la búsqueda coincida con elementos que la referencia no nombra, o con cada elemento del documento, por lo que qué nodo se selecciona para la verificación del resumen es decidido por la expresión inyectada en lugar de por la referencia. -
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/69ad2b421118fadd33d57f50b110b8d161e8fef5.patch Types: Patch Added Reference Type CPANSec: https://github.com/perl-net-saml2/perl-XML-Sig/commit/a85aad21aa767ac1c158bbfc19447683941ab376.patch Types: Patch Added Reference Type CPANSec: https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/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-2026-9390', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-03T19:58:29.107052Z'} -
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 XPath injection in ID lookup. verify() and _get_signed_xml() in lib/XML/Sig.pm build XPath expressions by concatenating the SignedInfo/Reference/@URI value read from the document being verified. The value is neither escaped nor checked against the NCName grammar that XML requires of an ID, so a URI containing a single quote closes the string literal in the generated expression and appends arbitrary XPath operators. A crafted URI can make the lookup match elements the reference does not name, or every element in the document, so which node is selected for digest verification is decided by the injected expression rather than by the reference. Added CWE CWE-643 Added CWE CWE-1287 Added Reference https://github.com/perl-net-saml2/perl-XML-Sig/commit/69ad2b421118fadd33d57f50b110b8d161e8fef5.patch Added Reference https://github.com/perl-net-saml2/perl-XML-Sig/commit/a85aad21aa767ac1c158bbfc19447683941ab376.patch Added Reference https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/changes