Use After Free in Ggml Llama.cpp
CVE-2026-43632
llama.cpp builds b7492 through the latest b9060 contains a use-after-free vulnerability in llama-server affecting six tokenization endpoints (/tokenize, /detokenize, /infill, /apply-template, /rerank, and /anthropic/count_tokens) that bypass the task queue and access ctx_server.vocab directly on HTTP worker threads. Attackers can exploit a time-of-check-time-of-use race condition where the main thread destroys and frees vocab after the synchronization lock is released but before the handler finishes using it, causing a crash or potential code execution when --sleep-idle-seconds is configured.
Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.005 (41.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 41.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Ggml Llama.cpp
- Ggml-Org Llama.cpp — versions b7492
Weakness classification (CWE)
References
- github.com/Vladimir-tokarev-cyera/llama-cpp-security-patches (Patch, Third Party Advisory, mitigation)
- www.vulncheck.com/advisories/llama-cpp-b7492-b9060-use-after-free-in-tokenizati… (Patch, Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-43632?
- CVE-2026-43632 is a high-severity vulnerability in Ggml Llama.cpp, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 8.1/10. Published 2026-08-06.
- How severe is CVE-2026-43632?
- High severity. CVSS v3 base score is 8.1 out of 10.