CVE-2023-47124 Denial of service whith ACME HTTPChallenge in Traefik
Attackers can cause denial of service in Traefik via slowloris attacks when HTTPChallenge is used for ACME certificate renewal.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-47124?
CVE-2023-47124 is a medium-severity denial of service vulnerability in Traefik Traefik, published on 4 Dec 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Traefik is an open source HTTP reverse proxy and load balancer. When Traefik is configured to use the `HTTPChallenge` to generate and renew the Let's Encrypt TLS certificates, the delay authorized to solve the challenge (50 seconds) can be exploited by attackers to achieve a `slowloris attack`. This vulnerability has been patch in version 2.10.6 and 3.0.0-beta5. Users are advised to upgrade. Users unable to upgrade should replace the `HTTPChallenge` with the `TLSChallenge` or the `DNSChallenge`.
Weakness: CWE-772
Which versions are affected by CVE-2023-47124?
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 | Affected | Fixed in |
|---|---|---|
github.com/traefik/traefik/v2 Go | All versions | 2.10.6 |
github.com/traefik/traefik/v2 Go | All versions | 2.10.6 |
github.com/traefik/traefik/v2 Go | All versions | 2.10.6 |
github.com/traefik/traefik Go | All versions | None |
github.com/traefik/traefik/v3 Go | All versions | 3.0.0-beta5 |
github.com/traefik/traefik/v3 Go | All versions | 3.0.0-beta5 |
1 more packages
github.com/traefik/traefik/v3 Go | All versions | 3.0.0-beta5 |
Products include Traefik Traefik.
How do I fix CVE-2023-47124?
Upgrade github.com/traefik/traefik/v2 to 2.10.6 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2023-47124 being exploited?
There is no known exploitation of CVE-2023-47124 in the wild and no public exploit code.
Other vulnerabilities in Traefik Traefik
- CVE-2024-45410 HTTP client can remove the X-Forwarded headers in Traefik
- CVE-2026-88877 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect
- CVE-2026-85595 Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth
- CVE-2026-88007 Traefik HTTP/3 Backend NTLM Connection Reuse
- CVE-2026-88009 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
Sources
Also known as ECHO-6d34-77d3-0a22, GHSA-8g85-whqh-cr2f, GO-2023-2381.