---
id: CVE-2026-88878
title: Traefik is an HTTP reverse proxy and load balancer
summary: >-
  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 defau…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cwe:
  - CWE-770
vendor: traefik
product: traefik
affected:
  - 'traefik >= 2.8.2, < 2.11.56'
  - 'traefik >= 3.0.0, < 3.7.12'
patched:
  - traefik 3.7.12
published: '2026-09-10'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T19:58:08.727'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88878'
references:
  - url: 'https://github.com/traefik/traefik/security/advisories/GHSA-7ghq-v6jf-g56c'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/traefik-2.8.2-through-3.6-http-3-timeout-bypass
    label: disclosure@vulncheck.com
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88878.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-88878'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2531451'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-88878'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88878'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - score-dispute
epss: 0.00423
epssPercentile: 0.33957
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-10T14:22:22.467169Z'
scores:
  nvd: 5.3
  vendor: 7.5
  cna: 5.3
ingestedAt: '2026-09-10T13:50:37.334Z'
---

## Overview

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

- `traefik >= 2.8.2, < 2.11.56`
- `traefik >= 3.0.0, < 3.7.12`

## Remediation

Upgrade past the affected range:

- `traefik 3.7.12`

## Vendor advisories

- **Red Hat VEX** · Important · affected: Red Hat OpenShift Dev Spaces · no fix planned: Red Hat OpenShift Dev Spaces · updated 2026-09-12 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-88878.json)