CVE-2023-37365 is a medium-severity (CVSS 6.5) CWE-415 vulnerability in hnswlib. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for hnswlib — see the affected versions and patch details below.
hnswlib Double Free vulnerability
Exploitation Status
No confirmed exploitation observed yet
- 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-2023-37365.
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
hnswlibReal-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
Hnswlib 0.7.0 has a double free in init_index when the M argument is a large integer.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | hnswlib | all versions | 0.8.0pip install --upgrade 'hnswlib==0.8.0' |
Affected Products
hnswlibhnswlib_projectResearch 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 hnswlib, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update hnswlib to 0.8.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-37365 is resolved across your whole dependency graph.
Workarounds
Constrain what reaches the vulnerable code: limit the size and shape of untrusted input, isolate the affected component in a sandboxed or least-privileged process, and enable the platform's memory-safety mitigations (ASLR, stack protector, hardened allocator) so an out-of-bounds access is more likely to fail closed than to be exploitable.
Frequently Asked Questions
Is CVE-2023-37365 in your dependencies?
Find it across PyPI, including transitive dependencies.