Classic Buffer Overflow in pyo

published 2021-12-17 4 y ago modified 2026-07-06 4 mo ago also GHSA-5f5c-687x-g5qm , PYSEC-2026-743 , EUVD-2022-0464

cvss: 7.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.4%; EPSS 1.4% chance of exploitation in 30 days, percentile 72%
public exploits: 0; none known

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.

Patch / fix

fixed in 2 distros 1

pypi pyo 1.0.3
pyo_project pyo 1.03

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

debian advisories DEBIAN-CVE-2021-41499

Exploit prediction

1.41% chance of exploitation in the next 30 days, higher than 72% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/belangeo/pyo/issues/222 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
GitHub	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV	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	<1.0.3	1.0.3

Classification

Weakness

CWE-120 Buffer Copy without Checking Size of Input

References

github.com /belangeo/pyo/issues/222
web, exploit, issue-tracking, third-party-advisory
nvd.nist.gov /vuln/detail/CVE-2021-41499
advisory
github.com /belangeo/pyo
package
pypi.org /project/pyo
package
github.com /advisories/GHSA-5f5c-687x-g5qm
advisory

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