Traefik v2.8.2 through v3.6 HTTP/3 Timeout Bypass
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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-88012US | — | — | ||
Traefik is an open source HTTP reverse proxy and load balancer. From 2.8.2 until 2.11.56 and 3.7.12, HTTP/3 entrypoints do not apply entryPoints..transport.respondingTimeouts.readT… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/88xxx/CVE-2026-88878.jsonADVISORY
- https://github.com/traefik/traefik/security/advisories/GHSA-7ghq-v6jf-g56cADVISORY
- https://nvd.nist.gov/vuln/detail/CVE-2026-88878ADVISORY
- https://www.vulncheck.com/advisories/traefik-2.8.2-through-3.6-http-3-timeout-bypassADVISORY
Advisories like this name the exposed products attackers go after on your perimeter. See what is exposed on your perimeter with a free passive scan.
Free scan