CVE-2026-88878

MEDIUM CVSS 4.0: 6.9 EPSS 0.30%
Updated Sep 14, 2026
Traefik
Parameter Value
CVSS 6.9 (MEDIUM)
Affected Versions 2.8.2 — 3.7.12
Fixed In 2.11.56
Type CWE-770 (Allocation Without Limits)
Vendor Traefik
Public PoC No

Traefik is an HTTP reverse proxy and load balancer. In versions >= v2.8.2 through <= v2.11.55 and >= v3.0.0 through <= v3.7.11, the entryPoints.<name>.transport.respondingTimeouts settings — notably readTimeout, which is enabled by default at 60s — are not applied to the HTTP/3 request path. readTimeout is enforced as a deadline on the underlying TCP connection, which cannot be applied to a QUIC stream, and Traefik's HTTP/3 server is constructed without any timeout. As a result, on entry points with HTTP/3 enabled, an unauthenticated remote client that trickles request body bytes can hold a request open indefinitely and, with it, one upstream connection per request, exhausting bounded backend connection pools and causing denial of service.

The issue was introduced in v2.8.2 when a quic-go API change removed the embedded http.Server that carried these timeouts. Fixed in v2.11.56 and v3.7.12.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
Low
Partial disruption

CVSS Vector v4.0

Vulnerable Products 2

Configuration From (including) Up to (excluding)
Traefik Traefik
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
2.8.2 2.11.56
Traefik Traefik
cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
3.0.0 3.7.12