Incorrect Implementation of Authentication Algorithm Affecting python-signxml package, versions <4.0.5+dfsg-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published3 Jun 2025
- disclosed2 Jun 2025
Introduced: 2 Jun 2025
CVE-2025-48994 (opens in a new tab)How to fix?
Upgrade Debian:unstable python-signxml to version 4.0.5+dfsg-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream python-signxml package and not the python-signxml package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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 algorithm confusion attack. Unless the user explicitly limits the expected signature algorithms using the signxml.XMLVerifier.verify(expect_config=...) setting, an attacker may supply a signature unexpectedly signed with a key other than the provided HMAC key, using a different (asymmetric key) signature algorithm. Starting with SignXML 4.0.4, specifying hmac_key causes the set of accepted signature algorithms to be restricted to HMAC only, if not already restricted by the user.