What is CVE-2020-24241?

CVE-2020-24241 is a medium-severity vulnerability in Nasm Netwide Assembler, classified under Use After Free. CVSS score: 5.5/10. Published 2020-08-25.

How severe is CVE-2020-24241?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Is CVE-2020-24241 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Use After Free in Nasm Netwide Assembler

CVE-2020-24241

In Netwide Assembler (NASM) 2.15rc10, there is heap use-after-free in saa_wbytes in nasmlib/saa.c.

Vulnerability class: Use-After-Free

Published 2020-08-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.008 (54.1th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Nasm Netwide Assembler — versions 2.15

Weakness classification (CWE)

CWE-416 — Use After Free

Public proof-of-concept exploits

ARPSyndicate/cve-scores

References

bugzilla.nasm.us/show_bug.cgi (Exploit, Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2020-24241?: CVE-2020-24241 is a medium-severity vulnerability in Nasm Netwide Assembler, classified under Use After Free. CVSS score: 5.5/10. Published 2020-08-25.
How severe is CVE-2020-24241?: Medium severity. CVSS v3 base score is 5.5 out of 10.
Is CVE-2020-24241 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.