CVE-2026-9390
XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
9.1
XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup
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.
- Record
CVE-2026-9390- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-643, CWE-1287
- Updated
- 2026-11-02
EUVDEUVD-2026-52269
9.1
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.
- Record
EUVD-2026-52269- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-mhmm-7px6-jx3j
9.1
XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup. verify() and...
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.
- Record
GHSA-mhmm-7px6-jx3j- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-643
- Updated
- 2026-11-02
NVD
9.1
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.
- Record
CVE-2026-9390- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-643, CWE-1287
- Updated
- 2026-11-02
OSV
9.1
XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup
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.
- Record
CVE-2026-9390- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-1287, CWE-643
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-9390 is a critical vulnerability (CVSS 9.1) in Timlegge Xml::sig, published August 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.51%, the 43rd percentile. No source names a fixed version.
References
github.com/perl-net-saml2/perl-XML-Sig/commit/69ad2b421118fadd33d57f50b110b8d161e8fef5.patch
github.com/perl-net-saml2/perl-XML-Sig/commit/a85aad21aa767ac1c158bbfc19447683941ab376.patch
metacpan.org/release/TIMLEGGE/XML-Sig-0.71/changes
nvd.nist.gov/vuln/detail/CVE-2026-9390
github.com/advisories/GHSA-mhmm-7px6-jx3j
cpan.org/modules
github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9390.json
github.com/perl-net-saml2/perl-XML-Sig