CVE-2023-37544 is a high-severity (CVSS 7.5) Improper Authentication vulnerability in org.apache.pulsar:pulsar-websocket. A fix is available for org.apache.pulsar:pulsar-websocket — see the affected versions and patch details below.
Apache Pulsar WebSocket Proxy: Improper Authentication for WebSocket Proxy Endpoint Allows DoS
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
org.apache.pulsar:pulsar-websocket☕org.apache.pulsar:pulsar-websocket☕org.apache.pulsar:pulsar-websocketReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Improper Authentication vulnerability in Apache Pulsar WebSocket Proxy allows an attacker to connect to the /pingpong endpoint without authentication.
This issue affects Apache Pulsar WebSocket Proxy: from 2.8.0 through 2.8., from 2.9.0 through 2.9., from 2.10.0 through 2.10.4, from 2.11.0 through 2.11.1, 3.0.0.
The known risks include a denial of service due to the WebSocket Proxy accepting any connections, and excessive data transfer due to misuse of the WebSocket ping/pong feature.
2.10 Pulsar WebSocket Proxy users should upgrade to at least 2.10.5. 2.11 Pulsar WebSocket Proxy users should upgrade to at least 2.11.2. 3.0 Pulsar WebSocket Proxy users should upgrade to at least 3.0.1. 3.1 Pulsar WebSocket Proxy users are unaffected. Any users running the Pulsar WebSocket Proxy for 2.8, 2.9, and earlier should upgrade to one of the above patched versions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.pulsar:pulsar-websocket | all versions | 2.10.5org.apache.pulsar:pulsar-websocket:2.10.5 |
| ☕Maven | org.apache.pulsar:pulsar-websocket | ≥ 2.11.0&&< 2.11.2 | 2.11.2org.apache.pulsar:pulsar-websocket:2.11.2 |
| ☕Maven | org.apache.pulsar:pulsar-websocket | ≥ 3.0.0&&< 3.0.1 | 3.0.1org.apache.pulsar:pulsar-websocket:3.0.1 |
Affected Products
pulsarapacheDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.pulsar:pulsar-websocket, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.pulsar:pulsar-websocket to 2.10.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-37544 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2023-37544 in your dependencies?
Find it across Maven, including transitive dependencies.