Unauthenticated code execution via sleep-transition race
Published Aug 6, 2026 · Updated Aug 6, 2026
Use-after-free in llama-server builds b7492 through b9060 allows remote attackers to execute arbitrary code through HTTP requests. During the sleep transition, the server frees model-owned vocabulary storage while concurrent request workers can still dereference its stale pointer, allowing the storage to be reclaimed with attacker-controlled data. The server must run with --sleep-idle-seconds enabled, and exploitation requires request timing that overlaps the transition; successful exploitation runs code with the server process's privileges.
Summary
What happened
Use-after-free in llama-server builds b7492 through b9060 allows remote attackers to execute arbitrary code through HTTP requests. During the sleep transition, the server frees model-owned vocabulary storage while concurrent request workers can still dereference its stale pointer, allowing the storage to be reclaimed with attacker-controlled data. The server must run with --sleep-idle-seconds enabled, and exploitation requires request timing that overlaps the transition; successful exploitation runs code with the server process's privileges.
The record
- CVE
- CVE-2026-43631
- Published
- Aug 6, 2026
- Updated
- Aug 6, 2026
- Vendor
- Georgi Gerganov
- Product
- llama.cpp
- Classifications
- CWE-362, CWE-416, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 6, 2026CVE publishedPublication date reported by the CVE source.
- Aug 6, 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?
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- Affected versionversion=b7492 <=b9060
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
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