Buffer overflow in Nasm
CVE-2026-6067
A heap buffer overflow vulnerability exists in the Netwide Assembler (NASM) due to a lack of bounds checking in the obj_directive() function. This vulnerability can be exploited by a user assembling a malicious .asm file, potentially leading to heap memory corruption, denial of service (crash), and arbitrary code execution.
Vulnerability class: Buffer Overflow
Published · last modified .
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: 0.004 (27.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 27.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: +0.000
Affected products
- Nasm — versions nasm-3.02rc5
- Nasm Netwide Assembler — versions 3.02
Weakness classification (CWE)
References
- github.com/netwide-assembler/nasm/issues/203 (Exploit, Issue Tracking)
Frequently asked questions
- What is CVE-2026-6067?
- CVE-2026-6067 is a medium-severity vulnerability in Nasm, classified under Out-of-bounds Write. CVSS score: 5.5/10. Published 2026-04-10.
- How severe is CVE-2026-6067?
- Medium severity. CVSS v3 base score is 5.5 out of 10.