Xml
CVE-2025-40934
CRITICAL
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Signature verification
|
| Impact | CVSS score of 9.3 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. EPSS exploitation probability: 0.02%. |
| Exploit ScenarioDerived | This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the critical-severity affected system. |
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Alert meAnalysisAIv1 – Mar 28, 2026
XML-Sig versions 0.27 through 0.67 for Perl incorrectly validates XML files if signatures are omitted. Rated critical severity (CVSS 9.3), this vulnerability is remotely exploitable, no authentication required, low attack complexity.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
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Technical ContextAI · show details
This vulnerability is classified under CWE-347. 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. Affected products include: Xml\ \. Version information: through 0.67.
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:N
Primary rating from Vendor (9b29abf9-4ab0-4765-b253-1875cd9b441e) · only source for this CVE.
CVSS VectorVendor: 9b29abf9-4ab0-4765-b253-1875cd9b441e
Lifecycle Timeline
2DescriptionCVE.org
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.
Executive ViewAI
CVE-2025-40934 presents critical security risk, a signature bypass vulnerability rated CVSS 9.3. Successful exploitation could critically impact the confidentiality, integrity, and availability of affected systems. A patch is available and should be applied immediately given the critical severity.
Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Affected Products (CPE)CVE.org
Malformed UTF-16 decoding in libexpat through 2.8.4 lets remote attackers hide XML markup from the parser: a lone high s
Signature-verification bypass in the Perl XML::Sig module before 0.71 allows remote attackers to forge which document no
Out-of-bounds read in the XML::Bare Perl XML parser (all releases through 0.53) lets a remote attacker crash the parsing
Signature verification bypass in the Perl XML::Sig module before 0.71 allows XML Signature Wrapping (XSW) via duplicate
Signature verification bypass in XML::Sig (Perl) versions 0.29 through 0.71 allows remote unauthenticated attackers to s
Denial of service in the Perl XML::Bare module (versions through 0.53) allows remote attackers to force an infinite loop
Out-of-bounds heap read in XML::LibXML for Perl (all versions through 2.0210) allows remote attackers to trigger denial-
Exploit-DB