CVE-2026-41263
Last modified
CVE-2026-41263 is a low-severity vulnerability rated 3.7/10 on the CVSS scale. Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a timing side-channel vulnerability in Traefik's BasicAuth middleware that allows an attacker to enumerate valid usernames through response-time differences. EPSS estimates a 0.37% chance of exploitation in the next 30 days.
Description
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a timing side-channel vulnerability in Traefik's BasicAuth middleware that allows an attacker to enumerate valid usernames through response-time differences. The variable intended to hold a constant-time fallback secret always resolves to an empty string, causing the constant-time comparison to short-circuit in microseconds rather than performing a full bcrypt evaluation. This restores the original timing oracle and makes it possible to distinguish existing users from non-existing ones by measuring authentication response times. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.
Metrics
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/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
Weakness Enumeration
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Traefik | Traefik | < 2.11.43 | — |
| Traefik | Traefik | >= 3.0.0, < 3.6.14 | — |
| Traefik | Traefik | 3.7.0 | Ea1 |
References
- https://github.com/traefik/traefik/releases/tag/v2.11.43Product, Release Notes
- https://github.com/traefik/traefik/releases/tag/v3.6.14Product, Release Notes
- https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2Product, Release Notes
- https://github.com/traefik/traefik/security/advisories/GHSA-6x2q-h3cr-8j2hPatch, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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