CVE-2026-25138 | Rucio WebUI has Username Enumeration via Login Error Message

Exp

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.

Published: 2026-02-25 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-25138 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.33%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-25138

EDB-ID Source Kind Published Link
nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-25138

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.05% 0.33% +0.28%
2 2026-03-21 0.03% 0.05% +0.02%
3 2026-02-26 0.03%

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-25138

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 1.4 [email protected]

Weakness enumeration for CVE-2026-25138

GitHub Security Advisory for CVE-2026-25138

GHSA-38wq-6q2w-hcf9 · Severity: medium · Ecosystem: pip — Rucio WebUI has Username Enumeration via Login Error Message

Affected software / configurations for CVE-2026-25138

Vendor Product Version Raw CPE
cern rucio < 35.8.3 cpe:2.3:a:cern:rucio:*:*:*:*:*:*:*:*
cern rucio >= 36.0.0, < 38.5.4 cpe:2.3:a:cern:rucio:*:*:*:*:*:*:*:*
cern rucio >= 39.0.0, < 39.3.1 cpe:2.3:a:cern:rucio:*:*:*:*:*:*:*:*

References for CVE-2026-25138

cvelogic Threat Intelligence