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Fencer Vulns
critical 9.3

CVE-2025-40934 json

XML-Sig prior to 0.68 for Perl improperly validates XML without signatures

published 2025-11-26 11 mo ago modified 2026-10-18 21 d ago also EUVD-2025-199778

cvss
9.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

XML-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 XML document to make it pass the verification check.

XML-Sig is a Perl module to validate signatures on XML files.  An unsigned XML file should return an error message.  The affected versions return true when attempting to validate an XML file that contains no signatures.

Patch / fix

  • TIMLEGGE XML::Sig 0.68
  • perl-xml-sig Alpine 3.24, Alpine 3.23, Alpine 3.22 0.68-r0

alpine advisories ALPINE-CVE-2025-40934

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
11 mo ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
CNA 3.1 9.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N

Affected products

  • TIMLEGGE XML::Sig

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.