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CVE-2026-26998

MEDIUM CVSS 3.1: 4.4 EPSS 0.04%
Updated Mar 06, 2026
Traefik
Parameter Value
CVSS 4.4 (MEDIUM)
Affected Versions 3.0.0 — 3.6.9
Fixed In 2.11.38
Type CWE-770 (Allocation Without Limits)
Vendor Traefik
Public PoC No

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.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
High
Admin privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v3.1

Vulnerable Products 2

Configuration From (including) Up to (excluding)
Traefik Traefik
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
2.11.38
Traefik Traefik
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
3.0.0 3.6.9