How severe is CVE-2025-40934?

CVE-2025-40934 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.

Is CVE-2025-40934 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-40934?

CVE-2025-40934 affects Xml. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-40934?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-40934 have an EU (EUVD) identifier?

Yes. CVE-2025-40934 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-199778.

When was CVE-2025-40934 published?

CVE-2025-40934 was published on 2025-11-26 and last updated on 2026-06-17.

CVE-2025-40934

CVE-2025-40934 is a critical-severity vulnerability in Xml with a CVSS 3.x base score of 9.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-347.

Key facts

Severity: Critical (CVSS 3.x base score 9.3)
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-199778
Weakness: CWE-347
Affected product: Xml
Published: 2025-11-26
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2025-40934?: 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.
How severe is CVE-2025-40934?: CVE-2025-40934 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2025-40934 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-40934?: CVE-2025-40934 affects Xml. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-40934?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-40934 have an EU (EUVD) identifier?: Yes. CVE-2025-40934 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-199778.
When was CVE-2025-40934 published?: CVE-2025-40934 was published on 2025-11-26 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:xml\:\:sig_project:xml\:\:sig:*:*:*:*:*:perl:*:*

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