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\Application · Xml\

CVE-2026-9390

CRITICAL · 9.1 CVSS v3.1 Published 2026-08-03
Fix available
A fix is available. Upgrade to 0.71 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 2 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
\Application
Affected:< 0.71

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 0.71 or later
Fixed in 0.71
Recommended fix High confidence

XML::Sig version 0.71

  1. Check the current version of XML::Sig installed: `perl -MXML::Sig -e 'print $XML::Sig::VERSION'
  2. Upgrade XML::Sig to version 0.71 using CPAN shell: `cpan XML::Sig` or `cpanm XML::Sig`
  3. Alternatively, force specific version: `cpanm XML::[email protected]`
  4. Verify the upgrade was successful by checking the new version again
  5. Run your application's test suite to confirm the XML signature verification still works correctly after the upgrade
Caveat Minimal risk - this is a security fix that patches the XPath injection vulnerability; ensure your application handles valid XML IDs correctly per NCName grammar

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,300. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-9390 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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