Pyo Buffer Overflow Vulnerability

published 2021-12-17 4 y ago modified 2026-06-17 4 mo ago also GHSA-qj27-32wp-ghrg , PYSEC-2021-890 , EUVD-2021-0475

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.2%; EPSS 1.2% chance of exploitation in 30 days, percentile 69%
public exploits: 0; none known

Buffer overflow in ajaxsoundstudio.com Pyo &lt 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.

Patch / fix

fixed in 1 distros 1 links 1

pypi pyo 1.0.4

python-pyo Debian 14, Debian 13, Debian 12 1.0.4-1

debian advisories DEBIAN-CVE-2021-41498

github.com/belangeo/pyo@017702c commit

Exploit prediction

1.23% chance of exploitation in the next 30 days, higher than 69% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/belangeo/pyo/issues/221 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	5.0	AV:N/AC:L/Au:N/C:N/I:N/A:P
OSV	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
pypi	pyo	<1.0.4	1.0.4

Classification

Weakness

CWE-120 Buffer Copy without Checking Size of Input

References

github.com /belangeo/pyo/commit/017702c73332a8560c8554a36250a6da587a2418
web
github.com /belangeo/pyo/issues/221
web, exploit, issue-tracking, third-party-advisory, report
nvd.nist.gov /vuln/detail/CVE-2021-41498
advisory
github.com /belangeo/pyo
package
github.com /pypa/advisory-database/tree/main/vulns/pyo/PYSEC-2021-890.yaml
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary