Vulnerability · Published Sep 10, 2026 · Assigned by VulnCheck
CVE-2026-88878Traefik v2.8.2 through v3.6 HTTP/3 Timeout Bypass
Medium 5.3
In plain English
A medium-severity resource allocation without limits in traefik from traefik. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Go | github.com/traefik/traefik | no fix listed | GO-2026-6454 |
| Go | github.com/traefik/traefik/v2 | 2.11.56 | GHSA-7ghq-v6jf-g56c |
| Go | github.com/traefik/traefik/v2 | 2.11.56 | GO-2026-6454 |
| Go | github.com/traefik/traefik/v3 | 3.7.12 | GHSA-7ghq-v6jf-g56c |
| Go | github.com/traefik/traefik/v3 | 3.7.12 | GO-2026-6454 |
Affected products (as reported)
Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
- GitHub Security Advisory (GHSA-7ghq-v6jf-g56c) vendor-advisory
- VulnCheck Advisory: Traefik v2.8.2 through v3.6 HTTP/3 Timeout Bypass third-party-advisory