Embedding-process crash via unchecked disassembly output length
Published Apr 10, 2026 · Updated Apr 10, 2026
Stack-based buffer overflow in NASM 3.02rc5 allows attackers to crash an embedding process by requesting disassembly into a small buffer. The disasm() function combines bounded formatting with unchecked direct writes and then writes output[slen] without ensuring slen remains below outbufsize. The public proof of concept calls this internal function directly; no path through the NASM or NDISASM command-line tools or a network service has been demonstrated.
Summary
What happened
Stack-based buffer overflow in NASM 3.02rc5 allows attackers to crash an embedding process by requesting disassembly into a small buffer. The disasm() function combines bounded formatting with unchecked direct writes and then writes output[slen] without ensuring slen remains below outbufsize. The public proof of concept calls this internal function directly; no path through the NASM or NDISASM command-line tools or a network service has been demonstrated.
The record
- CVE
- CVE-2026-6069
- Published
- Apr 10, 2026
- Updated
- Apr 10, 2026
- Vendor
- NASM
- Product
- NASM
- Classifications
- CWE-787
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Apr 10, 2026CVE publishedPublication date reported by the CVE source.
- Apr 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=nasm-3.02rc5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Issue 217 AddressSanitizer proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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