CVE-2026-25138 Rucio WebUI has Username Enumeration via Login Error Message
Unauthenticated attackers can enumerate valid usernames via distinct login error messages in the Rucio WebUI.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-25138?
CVE-2026-25138 is a medium-severity vulnerability in rucio, published on 25 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Rucio is a software framework that provides functionality to organize, manage, and access large volumes of scientific data using customizable policies. Prior to versions 35.8.3, 38.5.4, and 39.3.1, the WebUI login endpoint returns distinct error messages depending on whether a supplied username exists, allowing unauthenticated attackers to enumerate valid usernames. Versions 35.8.3, 38.5.4, and 39.3.1 fix the issue.
Weakness: CWE-204
Which versions are affected by CVE-2026-25138?
7 open source packages ship an affected version, including rucio-webui. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
rucio-webui PyPI | All versions | 35.8.3, 38.5.4, 39.3.1 |
rucio-webui PyPI | All versions | 35.8.3 |
rucio-webui PyPI | All versions | 35.8.3 |
rucio-webui PyPI | From 36.0.0rc1 | 38.5.4 |
rucio-webui PyPI | From 36.0.0rc1 | 38.5.4 |
rucio-webui PyPI | From 39.0.0rc1 | 39.3.1 |
1 more packages
rucio-webui PyPI | From 39.0.0rc1 | 39.3.1 |
Products include Cern Rucio.
How do I fix CVE-2026-25138?
Upgrade rucio-webui to a fixed version for your release line: 35.8.3, 38.5.4 or 39.3.1.
Is CVE-2026-25138 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-25138 exists.
Other vulnerabilities in rucio
- CVE-2026-29080 Rucio SQL Injection in FilterEngine Oracle JSON Path via DID Search API
- CVE-2026-29090 Rucio SQL injection in postgres_meta DID search path compromises PostgreSQL metadata database
- CVE-2026-25136 Rucio WebUI has a Reflected Cross-site Scripting Vulnerability
- CVE-2026-25733 Rucio WebUI Vulnerable to Stored Cross-site Scripting (XSS) through Custom Rule Function
- CVE-2026-25734 Rucio WebUI has Stored Cross-site Scripting (XSS) in RSE Metadata
Sources
Also known as GHSA-38wq-6q2w-hcf9, PYSEC-2026-3053.