Traefik Traefik
CVE-2026-88878
Traefik is an HTTP reverse proxy and load balancer. In versions >= v2.8.2 through = v3.0.0 through .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.
What this means for your business
- It affects Traefik. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
What to do
- 1Check whether your company or your suppliers run Traefik, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
Not sure if your company is exposed?
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Scoring
- CVSS
- 5.3 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- CVSS v4
- 6.9
- Weakness
- CWE-770
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-10
- Last modified
- 2026-09-14
- Sources
- NVD
Affected products
- Traefik Traefik2.8.2 - 2.11.56, 3.0.0 - 3.7.12
As listed in the NVD configuration data. Not a statement about your estate.