Vulnerability Description
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing the ForwardAuth middleware responses. When Traefik is configured to use the ForwardAuth middleware, the response body from the authentication server is read entirely into memory without any size limit. There is no maxResponseBodySize configuration to restrict the amount of data read from the authentication server response. If the authentication server returns an unexpectedly large or unbounded response body, Traefik will allocate unlimited memory, potentially causing an out-of-memory (OOM) condition that crashes the process. This results in a denial of service for all routes served by the affected Traefik instance. This issue has been patched in versions 2.11.38 and 3.6.9.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Traefik | Traefik | < 2.11.38 |
Related Weaknesses (CWE)
References
- https://github.com/traefik/traefik/releases/tag/v2.11.38ProductRelease Notes
- https://github.com/traefik/traefik/releases/tag/v3.6.9ProductRelease Notes
- https://github.com/traefik/traefik/security/advisories/GHSA-fw45-f5q2-2p4xPatchVendor Advisory
FAQ
What is CVE-2026-26998?
CVE-2026-26998 is a vulnerability with a CVSS score of 4.4 (MEDIUM). Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.38 and 3.6.9, there is a potential vulnerability in Traefik managing the ForwardAuth middleware responses. When Traefik is co...
How severe is CVE-2026-26998?
CVE-2026-26998 has been rated MEDIUM with a CVSS base score of 4.4/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-26998?
Check the references section above for vendor advisories and patch information. Affected products include: Traefik Traefik.