Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Rucio WebUI (rucio-webui) versions before 35.8.3, from 36.0.0rc1 before 38.5.4, and from 39.0.0rc1 before 39.3.1 are affected. An unauthenticated attacker can submit login attempts to the login endpoint and tell from the differing error messages whether a username exists, enabling username enumeration for later password guessing. Upgrade to 35.8.3, 38.5.4, or 39.3.1, depending on your release line.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 5.3 | Medium | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0037, the 31st percentile, on 7 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 15:03 UTC First seen by agentprime
- 31 Oct 2026, 15:03 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-38wq-6q2w-hcf9
- OSV: GHSA-38wq-6q2w-hcf9
- github.com/rucio/rucio/security/advisories/GHSA-38wq-6q2w-hcf9
- nvd.nist.gov/vuln/detail/CVE-2026-25138
- cheatsheetseries.owasp.org/cheatsheets/Authentication_Cheat_Sheet.html#authentication-and-error-messages
- github.com/rucio/rucio
- github.com/rucio/rucio/releases/tag/35.8.3
- github.com/rucio/rucio/releases/tag/38.5.4
- github.com/rucio/rucio/releases/tag/39.3.1