CVE-2026-88010 json
Traefik: BasicAuth singleflight coalescing reintroduces an unauthenticated username-enumeration timing oracle
published 2026-09-22 47 d ago modified 2026-11-04 4 d ago also GHSA-8fcf-v89g-xpg6 , GO-2026-6558 , EUVD-2026-84532
- cvss
- 5.3
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 23%
- public exploits
- 0
- none known
Summary
Traefik is an open source HTTP reverse proxy and load balancer. From 3.6.11 until 3.7.13, checkPassword in pkg/middlewares/auth/basic_auth.go constructs the BasicAuth singleflight key from the submitted password and stored secret. Concurrent requests for absent usernames therefore coalesce on one key while configured usernames perform separate password hashes, creating an unauthenticated timing discrepancy that reveals whether a username exists. Sequential checks remain cost-equalized, Traefik v2 and Digest authentication are not affected, and the issue does not disclose credentials or bypass authentication. This issue is fixed in version 3.7.13.
Patch / fix
- go github.com/traefik/traefik/v3 3.7.13
- traefik traefik 3.7.13
- traefik openSUSE Tumbleweed 3.7.13-1.1
opensuse advisories openSUSE-SU-2026:12076-1
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 47 d ago
Exploit prediction
0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N |
| CNA | 4.0 | 6.3 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| go | github.com/traefik/traefik/v3 | >=3.6.11, <3.7.13 |
3.7.13 |
| go | github.com/traefik/traefik | all versions |
no fix listed |
Affected products
- traefik traefik
Classification
- Weakness
-
- CWE-208 Observable Timing Discrepancy
References
-
github.com
/traefik/traefik/pull/13816
web, issue-tracking, patch
-
github.com
/traefik/traefik/commit/ddc1bf4660b85fd61fafdd821eb8216fb1a0b130
web, patch
-
github.com
/traefik/traefik/security/advisories/GHSA-8fcf-v89g-xpg6
web, vendor-advisory, patch, advisory
-
github.com
/traefik/traefik/releases/tag/v3.7.13
web, release-notes
-
nvd.nist.gov
/vuln/detail/CVE-2026-88010
advisory
-
github.com
/traefik/traefik
package
Sources
- CVE List CVE-2026-88010
- GitHub Advisory GHSA-8fcf-v89g-xpg6
- NVD CVE-2026-88010
- OSV GO-2026-6558
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