Resource exhaustion in Traefik
CVE-2026-88878
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.004 (35.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 35.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/traefik/traefik/security/advisories/GHSA-7ghq-v6jf-g56c (vendor-advisory, Patch, Vendor Advisory)
- www.vulncheck.com/advisories/traefik-2.8.2-through-3.6-http-3-timeout-bypass (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-88878?
- CVE-2026-88878 is a medium-severity vulnerability in Traefik, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 5.3/10. Published 2026-09-10.
- How severe is CVE-2026-88878?
- Medium severity. CVSS v3 base score is 5.3 out of 10.