Arbitrary file write via dangling response pointer
Published Apr 10, 2026 · Updated Apr 10, 2026
Heap use-after-free in NASM 3.02rc5 allows context-dependent attackers to write arbitrary files through a crafted response file. The -@ parser stores a pointer from its temporary buffer in global depend_file, frees the buffer in process_respfile(), then passes the stale filename to fopen(). Exploitation requires NASM to process attacker-controlled build inputs; the demonstrated Linux x86-64 chain redirects dependency output into a shell startup file for code execution.
Summary
What happened
Heap use-after-free in NASM 3.02rc5 allows context-dependent attackers to write arbitrary files through a crafted response file. The -@ parser stores a pointer from its temporary buffer in global depend_file, frees the buffer in process_respfile(), then passes the stale filename to fopen(). Exploitation requires NASM to process attacker-controlled build inputs; the demonstrated Linux x86-64 chain redirects dependency output into a shell startup file for code execution.
The record
- CVE
- CVE-2026-6068
- Published
- Apr 10, 2026
- Updated
- Apr 10, 2026
- Vendor
- NASM
- Product
- NASM
- Classifications
- CWE-416, T1203
- Attack vector
- local
- Privileges
- unauthenticated
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?
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.
Public exploit references
- Project SEKAI persistent file-write and code-execution exploitweaponized · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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