Use After Free in Ggml Llama.cpp
CVE-2026-43631
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.
Vulnerability class: Race Condition
EPSS: 0.004 (35.9th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Ggml Llama.cpp
- Ggml-org Llama.cpp — versions b7492
Weakness classification (CWE)
References
- disclosure@vulncheck.com (Patch, Third Party Advisory, mitigation)
- disclosure@vulncheck.com (Patch, Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-43631?
- CVE-2026-43631 is a high-severity vulnerability in Ggml Llama.cpp, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 8.1/10. Published 2026-08-06.
- How severe is CVE-2026-43631?
- High severity. CVSS v3 base score is 8.1 out of 10.