CVE-2025-48995
Publication date 2 June 2025
Last updated 10 July 2026
Ubuntu priority
Description
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| python-signxml | 26.04 LTS resolute |
Needs evaluation
|
| 24.04 LTS noble | Not in release | |
| 22.04 LTS jammy | Not in release | |
| 20.04 LTS focal | Not in release |
Severity score breakdown
CVSS version: CVSS v4.0
Base score
6.9 · Medium
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N