What is CVE-2021-34123?

CVE-2021-34123 is a critical-severity vulnerability in Atasm Project, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2023-07-18.

How severe is CVE-2021-34123?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Atasm Project

CVE-2021-34123

An issue was discovered on atasm, version 1.09. A stack-buffer-overflow vulnerability in function aprintf() in asm.c allows attackers to execute arbitrary code on the system via a crafted file.

Vulnerability class: Buffer Overflow

Published 2023-07-18 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (52.9th percentile), scored 2026-10-02.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Atasm Project — versions 1.09

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

sourceforge.net/p/atasm/bugs/23/ (Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2021-34123?: CVE-2021-34123 is a critical-severity vulnerability in Atasm Project, classified under Out-of-bounds Write. CVSS score: 9.8/10. Published 2023-07-18.
How severe is CVE-2021-34123?: Critical severity. CVSS v3 base score is 9.8 out of 10.