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VulnerabilityPublished

CVE-2025-8843: NASM Netwide Assember · Heap-based Buffer Overflow

Affects NASM Netwide AssemberSource CVE Database V5

0

Public exploit available · CVSS 4.8 Medium.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 4.0 base score
4.8Medium
How severe the flaw is on the 0–10 CVSS scale.
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:P

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 11 Aug 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: evidence found.

    CVSS exploit maturity: proof of concept public

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

  1. 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.
  2. Restrict Local Access: Limit local access to systems running NASM to trusted users only. Implement strict access controls and monitor for unauthorized local logins.
  3. Use Sandboxing: Run NASM processes within sandboxed or containerized environments to contain potential exploitation impact.
  4. Monitor Build Systems: Implement integrity checks and monitoring on build environments to detect anomalous behavior or unexpected process crashes.
  5. Avoid Using Release Candidates in Production: Since 2.17rc0 is a release candidate, avoid deploying it in production or critical environments.
  6. Apply Principle of Least Privilege: Ensure NASM runs with the minimum necessary privileges to reduce the impact of exploitation.
  7. Incident Response Preparedness: Prepare for potential exploitation by having incident response plans that include detection of local privilege escalations and memory corruption exploits.
  8. 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.

References

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