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🐍 PyPI
Not in CISA KEV
HIGH severity

CVE-2021-41499 — pyo

HIGH

CVE-2021-41499 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.

Classic Buffer Overflow in pyo

Also known asGHSA-5f5c-687x-g5qmPYSEC-2026-743
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs72th percentile — riskier than 72% of all scored CVEsHighest risk
0.00%0.63%1.27%1.90%0.5%1.4%1.4%1.4%1.4%May 26Sep 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-41499 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

1 pkg affected
🐍pyo

Real-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 Vulnerability exists in ajaxsoundstudio.com n Pyo < 1.03 in the Server_debug function, which allows remote attackers to conduct DoS attacks by deliberately passing on an overlong audio file name.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIpyoall versions1.0.3pip install --upgrade 'pyo==1.0.3'

Affected Products

1 product · 1 configurations
Application
pyopyo_project
< 1.03
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Buffer Overflow Vulnerability exists in ajaxsoundstudio.com n Pyo < 1.03…

github.comNVDDec 2021

Detection & mitigation playbook

Open-source dependency

  1. Detect

    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.

  2. Fix

    Update pyo to 1.0.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-41499 is resolved across your whole dependency graph.

  3. Workarounds

    Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Frequently Asked Questions

Buffer Overflow Vulnerability exists in ajaxsoundstudio.com n Pyo < 1.03 in the Server_debug function, which allows remote attackers to conduct DoS attacks by deliberately passing on an overlong audio file name.
O3 Security · Impact-Aware SCA

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CVE-2021-41499: pyo Memory Corruption — Fixed in 1.0.3