CVE-2022-33684 — pulsar-client
HIGHCVE-2022-33684 is a high-severity (CVSS 8.1) CWE-295 vulnerability in pulsar-client. 1 public exploit reference exists, so weaponization risk is real. A fix is available for pulsar-client — see the affected versions and patch details below.
Apache Pulsar C++/Python OAuth Clients prior to 3.0.0 were vulnerable to an MITM attack due to Disabled Certificate Validation
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2022-33684.
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-2022-33684 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 377,166 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
pulsar-client🐍pulsar-client🐍pulsar-client🐍pulsar-clientReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
The Apache Pulsar C++ Client does not verify peer TLS certificates when making HTTPS calls for the OAuth2.0 Client Credential Flow, even when tlsAllowInsecureConnection is disabled via configuration. This vulnerability allows an attacker to perform a man in the middle attack and intercept and/or modify the GET request that is sent to the ClientCredentialFlow 'issuer url'. The intercepted credentials can be used to acquire authentication data from the OAuth2.0 server to then authenticate with an Apache Pulsar cluster. An attacker can only take advantage of this vulnerability by taking control of a machine 'between' the client and the server. The attacker must then actively manipulate traffic to perform the attack. The Apache Pulsar Python Client wraps the C++ client, so it is also vulnerable in the same way. This issue affects Apache Pulsar C++ Client and Python Client versions 2.7.0 to 2.7.4; 2.8.0 to 2.8.3; 2.9.0 to 2.9.2; 2.10.0 to 2.10.1; 2.6.4 and earlier. Any users running affected versions of the C++ Client or the Python Client should rotate vulnerable OAuth2.0 credentials, including client_id and client_secret. 2.7 C++ and Python Client users should upgrade to 2.7.5 and rotate vulnerable OAuth2.0 credentials. 2.8 C++ and Python Client users should upgrade to 2.8.4 and rotate vulnerable OAuth2.0 credentials. 2.9 C++ and Python Client users should upgrade to 2.9.3 and rotate vulnerable OAuth2.0 credentials. 2.10 C++ and Python Client users should upgrade to 2.10.2 and rotate vulnerable OAuth2.0 credentials. 3.0 C++ users are unaffected and 3.0 Python Client users will be unaffected when it is released. Any users running the C++ and Python Client for 2.6 or less should upgrade to one of the above patched versions.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pulsar-client | all versions | 2.7.5pip install --upgrade 'pulsar-client==2.7.5' |
| 🐍PyPI | pulsar-client | ≥ 2.8.0&&< 2.8.4 | 2.8.4pip install --upgrade 'pulsar-client==2.8.4' |
| 🐍PyPI | pulsar-client | ≥ 2.9.0&&< 2.9.3 | 2.9.3pip install --upgrade 'pulsar-client==2.9.3' |
| 🐍PyPI | pulsar-client | ≥ 2.10.0&&< 2.10.2 | 2.10.2pip install --upgrade 'pulsar-client==2.10.2' |
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 pulsar-client, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pulsar-client to 2.7.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2022-33684 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-2022-33684 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2022-33684. 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-2022-33684 in your dependencies?
O3 Security finds CVE-2022-33684 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.