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Vulnerability record · CVE-2026-43631 · published 6 August 2026

CVE-2026-43631: Ggml llama.cpp race condition vulnerability

Ggml · Llama.Cpp

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.

9.2 CVSS 4.0 Critical EPSS 0.57% · top 54.9% CWE-362 · Race conditionCWE-416 · Use after free
9.2CVSS 4.0 base score
0.57%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References
21 Sep 2026Last modified by NVD

Description

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.

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/Vladimir-tokarev-cyera/llama-cpp-security-patches PatchThird Party Advisory
https://www.vulncheck.com/advisories/llama-cpp-b7492-b9060-use-after-free-rce-via-llama-server PatchThird Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2026-34159Ggml llama.cpp memory buffer overflow vulnerabilityllama.cpp is an inference of several LLM models in C/C++. Prior to version b8492, the RPC backend's deserialize_tensor() skips all bounds validation …EPSS 1.2%9.8CVE-2026-21869Ggml llama.cpp out-of-bounds write vulnerabilityllama.cpp is an inference of several LLM models in C/C++. In commits 55d4206c8 and prior, the n_discard parameter is parsed directly from JSON input …EPSS 0.52%9.8CVE-2024-42478Ggml llama.cpp out-of-bounds read vulnerabilityllama.cpp provides LLM inference in C/C++. The unsafe `data` pointer member in the `rpc_tensor` structure can cause arbitrary address reading. This v…EPSS 0.60%9.8CVE-2024-42479Ggml llama.cpp out-of-bounds write vulnerabilityllama.cpp provides LLM inference in C/C++. The unsafe `data` pointer member in the `rpc_tensor` structure can cause arbitrary address writing. This v…EPSS 2.6%9.8CVE-2024-23605Ggml llama.cpp integer overflow vulnerabilityA heap-based buffer overflow vulnerability exists in the GGUF library header.n_kv functionality of llama.cpp Commit 18c2e17. A specially crafted .ggu…EPSS 1.3%9.8CVE-2024-23496Ggml llama.cpp integer overflow vulnerabilityA heap-based buffer overflow vulnerability exists in the GGUF library gguf_fread_str functionality of llama.cpp Commit 18c2e17. A specially crafted .…EPSS 1.3%9.8CVE-2024-21802Ggml llama.cpp heap-based buffer overflow vulnerabilityA heap-based buffer overflow vulnerability exists in the GGUF library info->ne functionality of llama.cpp Commit 18c2e17. A specially crafted .ggu…EPSS 1.4%9.8CVE-2024-21825Ggml llama.cpp integer overflow vulnerabilityA heap-based buffer overflow vulnerability exists in the GGUF library GGUF_TYPE_ARRAY/GGUF_TYPE_STRING parsing functionality of llama.cpp Commit 18c2…EPSS 1.3%

Source: NIST National Vulnerability Database (record CVE-2026-43631), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.