CVE-2025-48995
June 02, 2025
SignXML is an implementation of the W3C XML Signature standard in Python. When verifying signatures with X509 certificate validation turned off and HMAC shared secret set ("signxml.XMLVerifier.verify(require_x509=False, hmac_key=..."), versions of SignXML prior to 4.0.4 are vulnerable to a potential timing attack. The verifier may leak information about the correct HMAC when comparing it with the user supplied hash, allowing users to reconstruct the correct HMAC for any data.
Affected Packages
https://github.com/XML-Security/signxml.git (GITHUB):
Affected version(s) >=v0.1.0 <v4.0.4Fix Suggestion:
Update to version v4.0.4signxml (PYTHON):
Affected version(s) >=0.0.1 <4.0.4Fix Suggestion:
Update to version 4.0.4Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.9
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
LOW
Vulnerable System Integrity
NONE
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
NONE
Weakness Type (CWE)
Observable Timing Discrepancy
EPSS
Base Score:
0.08
