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Vulnerability record · CVE-2026-9390 · published 3 August 2026

CVE-2026-9390: Xml\ \ vulnerability

XXml\ · \

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.

9.1 CVSS 3.1 Critical EPSS 0.51% · top 59.3% CWE-643 · CWE-643CWE-1287 · CWE-1287
9.1CVSS 3.1 base score
0.51%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
3References
5 Aug 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/perl-net-saml2/perl-XML-Sig/commit/69ad2b421118fadd33d57f50b110b8d161e8fef5.patch Patch
https://github.com/perl-net-saml2/perl-XML-Sig/commit/a85aad21aa767ac1c158bbfc19447683941ab376.patch Patch
https://metacpan.org/release/TIMLEGGE/XML-Sig-0.71/changes Release Notes

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.3CVE-2025-40934Xml\ \ improper verification of cryptographic signature vulnerabilityXML-Sig versions 0.27 through 0.67 for Perl incorrectly validates XML files if signatures are omitted. An attacker can remove the signature from the …EPSS 0.16%9.1CVE-2026-9487Xml\ \ improper verification of cryptographic signature vulnerabilityXML::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…EPSS 0.28%7.5CVE-2026-18568Xml\ \ improper verification of cryptographic signature vulnerabilityXML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns true when every signature was skipped bef…EPSS 0.32%7.5CVE-2012-1102Xml\ \ xml external entity (xxe) vulnerabilityIt was discovered that the XML::Atom Perl module before version 0.39 did not disable external entities when parsing XML from potentially untrusted so…EPSS 1.4%

Source: NIST National Vulnerability Database (record CVE-2026-9390), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.