CVE-2025-48994 Details
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 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.
A vulnerability exists in SignXML, a Python library for XML signature processing, in versions prior to 4.0.4. When verifying signatures with X509 certificate validation disabled and an HMAC shared secret provided, the library is susceptible to an algorithm confusion attack. This vulnerability allows an attacker to exploit the signature verification process by using a different asymmetric signature algorithm, potentially leading to unauthorized actions or bypassing security controls. The issue arises because, by default, the library does not restrict the accepted signature algorithms, leaving room for exploitation.
Users can upgrade to SignXML version 4.0.4 or later, where the vulnerability has been addressed. In addition, when using HMAC keys, it is recommended to explicitly restrict the expected signature algorithms to HMAC only, unless already done.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jun 2, 2025CISA-ADP
Assessed Jun 2, 2025References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/XML-Security/signxml/commit/e3c0c2b82a3329a65d917830657649c98b8c7600 | [email protected] | Source CodeVendor |
| https://github.com/XML-Security/signxml/security/advisories/GHSA-6vx8-pcwv-xhf4 | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-303 | Incorrect Implementation of Authentication Algorithm | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| XML-Security SignXML | All versions |
CPE
Remediation
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Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Jun 2, 2025 | New CVE Received | [email protected] |