# Traefik: HTTP/3 mTLS bypass via exact SNI TLSOptions lookup for wildcard and mixed-case hosts Advisory record · `GHSA-9cr8-q42q-g8m7` - **Identifiers:** `GHSA-9cr8-q42q-g8m7` · `CVE-2026-53622` · `GO-2026-5287` - **State:** Confirmed - **Severity:** CVSS 7.8 High - **Critical:** No - **Weakness (CWE):** [CWE-288](https://cwe.mitre.org/data/definitions/288.html) · [CWE-289](https://cwe.mitre.org/data/definitions/289.html) - **Tags:** [Authentication bypass](https://agentprime.io/advisories/tag/auth-bypass.md) · [CWE-289](https://agentprime.io/advisories/tag/cwe-289.md) - **Published:** 16 Jun 2026 - **Updated:** 10 Sept 2026 - **Reviewed by a person:** No Published by the GitHub Advisory Database at 16 Jun 2026, 21:04 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. ## Affected packages - `github.com/traefik/traefik/v3` (Go): affected `>=3.7.0, <3.7.3 || <3.6.18`; fixed in `3.7.3`, `3.6.18` - `github.com/traefik/traefik/v2` (Go): affected `<2.11.51`; fixed in `2.11.51` - `github.com/traefik/traefik` (Go): affected `<=1.7.34`; no fixed version yet ## Machine-written summary Summary written by Claude Haiku from the source advisory. Not reviewed by a person. > Traefik v3 versions before 3.6.18 and from 3.7.0 before 3.7.3, Traefik v2 before 2.11.51, and Traefik v1 at or below 1.7.34 are affected, with fixes in 3.6.18, 3.7.3, and 2.11.51; no fix is listed for v1. When HTTP/3 is enabled, TLS option lookup is case-sensitive and exact, so a router's mTLS requirement can be skipped for wildcard or mixed-case hostnames. An unauthenticated client that can reach the UDP entrypoint may then reach a backend that requires client certificates. Upgrade to a fixed version, or disable HTTP/3 on affected entrypoints as a workaround. Written 1 Nov 2026. ## Not analysed yet We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check. ## Severity and exploitation - 7.8 High, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N`, from CNA (GitHub_M) - **CISA KEV:** Not listed. - **EPSS:** 0.0063, the 50th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days. ## Timeline - 31 Oct 2026, 14:14 UTC: First seen by agentprime - 31 Oct 2026, 14:14 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-9cr8-q42q-g8m7) ## Sources - [GitHub Advisory Database: GHSA-9cr8-q42q-g8m7](https://github.com/advisories/GHSA-9cr8-q42q-g8m7) - [OSV: GHSA-9cr8-q42q-g8m7](https://osv.dev/vulnerability/GHSA-9cr8-q42q-g8m7) - - - - - - - - - - - Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code. ## Check whether this affects you A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet. - With the agentprime MCP server (), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: - In a browser: reads your lockfile in the browser, never uploading it. - Whether it touches your code, with file and line: the Claude Code plugin, - As JSON: , or `POST https://api.agentprime.io/v1/match` with your packages () --- The web page: . Everything for agents: .