High [CVE-2026-43631] Remote code execution via use-after-free vulnerability in llama-server
This high-severity Red Hat Linux advisory covers CVE-2026-43631.
Android app · Google Play
Monitor future Red Hat Linux CVEs from your phone.
Choose a whole vendor or a precise platform, then receive matching security advisories by phone notification, email, or both. Coverage follows 32 official vendor sources and 160+ reviewed platform categories.
Summary
llama.cpp builds b7492 through the latest b9060 contains a use-after-free vulnerability in the vocab pointer of llama-server when the --sleep-idle-seconds feature is enabled, allowing unauthenticated remote attackers to execute arbitrary code.
Attackers can trigger the vulnerability by sending requests to affected endpoints while the server transitions to sleep mode, causing concurrent worker threads to dereference a freed vocab pointer that can be reclaimed with attacker-controlled data to achieve remote code execution.
Exploitation requires sending network requests to the HTTP server during the specific, narrow window when the service transitions into an idle sleep state.
If successfully timing the race condition, an unauthenticated attacker could corrupt server memory to achieve full compromise across Confidentiality, Integrity, and Availability (C:H, I:H, A:H) within the process privilege context.
Deployments operating without automated idle-sleep timeouts enabled, CLI tool invocations, or non-server API environments are completely unaffected by this flaw. Red Hat severity: Important — CVSS 8.1 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H).
Weakness: CWE-825.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- To mitigate this vulnerability, disable the `--sleep-idle-seconds` feature in the llama-server configuration. This feature is a prerequisite for the vulnerability to be exploited. Consult the llama.cpp documentation for specific instructions on disabling server features. A restart of the llama-server may be required for the changes to take effect.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Discussion(0)
No comments yet. Share field notes, upgrade gotchas, or questions — verify against the vendor advisory before acting on community advice.
Sign in to join the discussion.