CVE-2021-41498 is a high-severity (CVSS 7.5) CWE-120 vulnerability in pyo. 1 public exploit reference exists, so weaponization risk is real. A fix is available for pyo — see the affected versions and patch details below.
Pyo Buffer Overflow Vulnerability
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-41498 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
pyoReal-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
Buffer overflow in ajaxsoundstudio.com Pyo < and 1.03 in the Server_jack_init function. which allows attackers to conduct Denial of Service attacks by arbitrary constructing a overlong server name.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pyo | all versions | 1.0.4pip install --upgrade 'pyo==1.0.4' |
Affected Products
pyopyo_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 pyo, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pyo to 1.0.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41498 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-2021-41498 in your dependencies?
Find it across PyPI, including transitive dependencies.