CVE-2023-47633 — v2
HIGHCVE-2023-47633 is a high-severity (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in github.com/traefik/traefik/v2. 1 public exploit reference exists, so weaponization risk is real. A fix is available for github.com/traefik/traefik/v2 — see the affected versions and patch details below.
Uncontrolled Resource Consumption in Traefik
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2023-47633.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2023-47633 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/traefik/traefik/v2🐹github.com/traefik/traefik/v3Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
The traefik docker container uses 100% CPU when it serves as its own backend, which is an automatically generated route resulting from the Docker integration in the default configuration.
Details
While attempting to set up Traefik to handle traffic for Docker containers, I observed in the webUI a rule with the following information:
Host(traefik-service) | webwebsecure | traefik-service@docker | traefik-service
I assumed that this is something internal; however, I wondered why it would have a host rule on the web entrypoint configured.
So I have send a request with that hostname with curl -v --resolve "traefik-service:80:xxx.xxx.xxx.xxx" http://traefik-service. That made my whole server unresponsive.
I assume the name comes from a docker container with that name, traefik itself:
localhost ~ # docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d1414e74aec7 traefik:v2.10 "/entrypoint.sh trae…" 4 minutes ago Up 4 minutes 0.0.0.0:80->80/tcp, :::80->80/tcp, 0.0.0.0:443->443/tcp, :::443->443/tcp, 127.0.0.1:8080->8080/tcp traefik.service
PoC
-
Start traefik with
docker run --rm -v /var/run/docker.sock:/var/run/docker.sock -p 80:80 --name foo -p 8080:8080 traefik:v2.10 --api.insecure=true --providers.docker -
curl -v --resolve "foo:80:127.0.0.1" http://foo
looks like this creates an endless loop of request.
Knowing the name of the docker container seems to be enough to trigger this, if the docker backend is used.
Impact
Server is unreachable and uses 100% CPU
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/traefik/traefik/v2 | all versions | 2.10.6go get github.com/traefik/traefik/v2@v2.10.6 |
| 🐹Go | github.com/traefik/traefik/v3 | all versions | 3.0.0-beta5go get github.com/traefik/traefik/v3@v3.0.0-beta5 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/traefik/traefik/v2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/traefik/traefik/v2 to 2.10.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-47633 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-47633 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2023-47633. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2023-47633 in your dependencies?
O3 Security finds CVE-2023-47633 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.