# CVE-2026-22045: Traefik's ACME TLS-ALPN fast path lacks timeouts and close on handshake stall

> Malicious clients can cause denial of service in Traefik by stalling ACME TLS-ALPN handshakes, exhausting resources when this feature is enabled.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Jan 2026
- **Updated:** 20 Jan 2026
- **Also known as:** CLEANSTART-2026-DQ38367, GHSA-cwjm-3f7h-9hwq, GO-2026-4322, MINI-5636-qgx9-pp49, MINI-r8hg-qqw7-44pq

## What is CVE-2026-22045?

CVE-2026-22045 is a medium-severity denial of service vulnerability in Traefik Traefik, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Traefik is an HTTP reverse proxy and load balancer. Prior to 2.11.35 and 3.6.7, there is a potential vulnerability in Traefik ACME TLS certificates' automatic generation: the ACME TLS-ALPN fast path can allow unauthenticated clients to tie up go routines and file descriptors indefinitely when the ACME TLS challenge is enabled. A malicious client can open many connections, send a minimal ClientHello with acme-tls/1, then stop responding, leading to denial of service of the entry point. The vulnerability is fixed in 2.11.35 and 3.6.7.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-22045?

7 open source packages ship an affected version, including github.com/traefik/traefik/v2, github.com/traefik/traefik and github.com/traefik/traefik/v3. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.11.35 |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.11.35 |
| `github.com/traefik/traefik/v2` | Go | All versions | 2.11.35 |
| `github.com/traefik/traefik` | Go | All versions | None |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.7 |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.7 |
| `github.com/traefik/traefik/v3` | Go | All versions | 3.6.7 |

Products: Traefik Traefik.

## How do I fix CVE-2026-22045?

Upgrade github.com/traefik/traefik/v2 to 2.11.35 or later.

## Is CVE-2026-22045 being exploited?

There is no known exploitation of CVE-2026-22045 in the wild and no public exploit code.

## Other vulnerabilities in Traefik Traefik

- [CVE-2024-45410](https://insights.sbomify.com/CVE-2024-45410/): HTTP client can remove the X-Forwarded headers in Traefik (critical 9.8)
- [CVE-2026-88877](https://insights.sbomify.com/CVE-2026-88877/): Traefik v3.7.0 Authentication Bypass via from-to-www-redirect (critical 9.3)
- [CVE-2026-85595](https://insights.sbomify.com/CVE-2026-85595/): Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth (critical 9.3)
- [CVE-2026-88007](https://insights.sbomify.com/CVE-2026-88007/): Traefik HTTP/3 Backend NTLM Connection Reuse (critical 9.1)
- [CVE-2026-88009](https://insights.sbomify.com/CVE-2026-88009/): Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22045 and fix it if it is affected.

What it is: CVE-2026-22045 is a medium-severity denial of service vulnerability in Traefik Traefik, published on 15 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-22045 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.35
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.35
- github.com/traefik/traefik/v2 (Go): affected all versions; fixed in 2.11.35
- github.com/traefik/traefik (Go): affected all versions; no fix listed
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.7
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.7
- github.com/traefik/traefik/v3 (Go): affected all versions; fixed in 3.6.7

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-22045/ (Markdown: https://insights.sbomify.com/CVE-2026-22045/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22045
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22045
- OSV: https://osv.dev/vulnerability/CVE-2026-22045

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-22045/
Summaries are generated and may contain mistakes; the official description above is the record.