CVE-2025-8843: NASM Netwide Assember · Heap-based Buffer Overflow
Affects NASM Netwide AssemberSource CVE Database V5
Public exploit available · CVSS 4.8 Medium.
Data as of 26 Oct 2026, 10:12 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 18% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:PExploitation evidence
Disclosed: evidence found.
CVE published 11 Aug 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
CVSS exploit maturity: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CVSS vector, the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
- Upgrade NASM: Immediately upgrade to a NASM version later than 2.17rc0 once a patched release is available. Monitor official NASM channels for security updates.
- Restrict Local Access: Limit local access to systems running NASM to trusted users only. Implement strict access controls and monitor for unauthorized local logins.
- Use Sandboxing: Run NASM processes within sandboxed or containerized environments to contain potential exploitation impact.
- Monitor Build Systems: Implement integrity checks and monitoring on build environments to detect anomalous behavior or unexpected process crashes.
- Avoid Using Release Candidates in Production: Since 2.17rc0 is a release candidate, avoid deploying it in production or critical environments.
- Apply Principle of Least Privilege: Ensure NASM runs with the minimum necessary privileges to reduce the impact of exploitation.
- Incident Response Preparedness: Prepare for potential exploitation by having incident response plans that include detection of local privilege escalations and memory corruption exploits.
- Code Review and Static Analysis: Incorporate static analysis tools to detect similar memory handling issues in custom assembler code or related tools.
Description
A vulnerability was found in NASM Netwide Assember 2.17rc0. This affects the function macho_no_dead_strip of the file outmacho.c. The manipulation leads to heap-based buffer overflow. Local access is required to approach this attack. The exploit has been disclosed to the public and may be used.