CVE-2023-47124
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedTraefik 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`.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceWhen Traefik is configured to use the HTTPChallenge for Let's Encrypt TLS certificate generation/renewal, it must wait up to 50 seconds for clients to solve the HTTP-01 challenge. Attackers can exploit this window by initiating many concurrent certificate challenge requests and holding connections open, effectively conducting a slowloris-style denial-of-service attack against the Traefik server.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 2.10.5= 3.0.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify installed Traefik versionRun `traefik --version` or check the container/Docker image tagAffected if The version is 2.10.5 or lower, or exactly 3.0.0
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Locate Traefik configuration fileFind the static and/or dynamic configuration file (traefik.yml, traefik.toml, or CLI arguments) being usedAffected if Configuration file exists and is being used by the Traefik instance
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Check for HTTPChallenge provider in ACME settingsSearch the configuration for `httpChallenge` or `HTTPChallenge` under the ACME (Let's Encrypt) settings. Look for entries like `entryPoint: http` or `entryPoint: web` within the httpChallenge sectionAffected if The httpChallenge block is present and configured, indicating HTTP-01 challenge is enabled
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Verify active entry points accepting HTTP trafficCheck the static configuration for enabled entry points. Confirm if port 80 (http) or port 80 entry point is exposed and linked to the HTTPChallengeAffected if An HTTP entry point (typically port 80) is open and tied to the HTTPChallenge configuration, creating the vulnerable window
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Inspect ACME certificate storage for recent challenge activityCheck the ACME certificates storage location (default: `.traefik/cacerts` or similar) for recently created challenge files or look for logs indicating certificate challengesAffected if Certificate challenges using HTTP-01 are actively being processed or were recently processed, confirming the vulnerable feature is in use
You are affected if your Traefik version is 2.10.5 or lower (or exactly 3.0.0) AND the HTTPChallenge is configured in your ACME/Let's Encrypt settings, enabling the 50-second window vulnerable to slowloris-style attacks.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade to Traefik version 2.10.6 or 3.0.0-beta5, or alternatively replace HTTPChallenge with TLSChallenge or DNSChallenge which are not vulnerable to this timing-based attack vector.
2.10.6 or later for 2.x; 3.0.0-beta5 or later for 3.x
- Upgrade Traefik to version 2.10.6 or later if using the 2.x line
- Alternatively, if using the 3.x line, upgrade to version 3.0.0-beta5 or later
- If unable to upgrade, reconfigure Traefik to use TLSChallenge or DNSChallenge instead of HTTPChallenge for Let's Encrypt certificate generation
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-47124 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-47124 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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