CVE-2026-9390: XML::Sig versions before 0.71 for Perl allow XPath injection in ID lookup. verify() and _get_signed_xml() in

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CRITICAL 9.1REMOTEUPGRADE

CVE-2026-9390 is a critical-severity flaw (CVSS 9.1) affecting \. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 XP

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-643, CWE-1287
Published	2026-08-03
Last modified	2026-10-23

Publisher (CNA): CPANSec · Vendor: xml\

Am I affected?

Timeline

2026-08-03 14:16 UTCPublished CVE record published
2026-10-23 21:10 UTCUpdated Record last modified

xml\ \ UPGRADE

Affected: < 0.71

Fixed in: 0.71

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy || rpm -q || --version

2. UPGRADE to 0.71 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Exact fixes by distribution

Fedora 46 · rubygem-eventmachine · FIXED · 1.2.7-37.fc46 · FEDORA-2026-7194c202a2 · source

sudo dnf upgrade --advisory=FEDORA-2026-7194c202a2

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Related CVEs

CVE-2026-9487 CRITICAL 9.1 UPGRADE XML::Sig versions before 0.71 for Perl allow signature wrapping via duplicate ID. _get_signed_xml() in lib/XM
CVE-2026-18568 HIGH 7.5 UPGRADE XML::Sig versions from 0.29 before 0.72 for Perl allow signature verification bypass because verify returns tr

References

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