# CVE-2025-48995: python-signxml: SignXML is an implementation of the W3C XML Signature standard in Python

CVE-2025-48995 is fixed in python-signxml on 1 platform, first by DEBIAN-CVE-2025-48995, released June 2, 2025. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2025-48995
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0024
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jun 2, 2025

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | python-signxml Debian 13.5 (trixie) | 4.0.5+dfsg-1 | [DEBIAN-CVE-2025-48995](https://patchblox.com/security/data/fix/linux/debian-cve-2025-48995.md) | Jun 2, 2025 |
| Linux | python-signxml Debian 14 | 4.0.5+dfsg-1 | [DEBIAN-CVE-2025-48995](https://patchblox.com/security/data/fix/linux/debian-cve-2025-48995.md) | Jun 2, 2025 |

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Data as of 2026-11-08T06:59:42Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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