Traefik
CVE-2026-26998
MEDIUM
GHSA-fw45-f5q2-2p4x
Severity by source
AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
Lifecycle Timeline
3DescriptionGitHub Advisory
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.
AnalysisAI
Traefik versions prior to 2.11.38 and 3.6.9 fail to limit memory allocation when processing ForwardAuth middleware responses, allowing a malicious or compromised authentication server to trigger unbounded memory consumption. An attacker controlling the auth server can return an arbitrarily large response body that causes the Traefik process to exhaust available memory and crash, resulting in denial of service for all proxied routes. A patch is available in the specified versions.
Technical ContextAI
This vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) exists in the a denial of component. 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 re
RemediationAI
A vendor patch is available — apply it immediately. Restrict network access to the affected service where possible.
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Same technique Denial Of Service
View allVendor StatusVendor
SUSE
Severity: Medium| Product | Status |
|---|---|
| openSUSE Tumbleweed | Fixed |
| openSUSE Leap 15.6 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Fixed |
| openSUSE Leap 15.5 | Fixed |
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External POC / Exploit Code
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