CVE-2026-34159
CVE-2026-34159 is a critical-severity vulnerability in Ggml Llama.cpp with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- EPSS exploit prediction: 1% (62nd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-17975
- Weakness: CWE-119
- Affected product: Ggml Llama.cpp
- Published:
- Last modified:
Description
llama.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 when a tensor's buffer field is 0. An unauthenticated attacker can read and write arbitrary process memory via crafted GRAPH_COMPUTE messages. Combined with pointer leaks from ALLOC_BUFFER/BUFFER_GET_BASE, this gives full ASLR bypass and remote code execution. No authentication required, just TCP access to the RPC server port. This issue has been patched in version b8492.
Frequently asked questions
- What is CVE-2026-34159?
- llama.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 when a tensor's buffer field is 0. An unauthenticated attacker can read and write arbitrary process memory via crafted GRAPH_COMPUTE messages. Combined with pointer leaks from ALLOC_BUFFER/BUFFER_GET_BASE, this gives full ASLR bypass and remote code execution. No authentication required, just TCP access to the RPC server port. This issue has been patched in version b8492.
- How severe is CVE-2026-34159?
- CVE-2026-34159 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-34159 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (62nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-34159?
- CVE-2026-34159 affects Ggml Llama.cpp. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-34159?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2026-34159 have an EU (EUVD) identifier?
- Yes. CVE-2026-34159 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-17975.
- When was CVE-2026-34159 published?
- CVE-2026-34159 was published on 2026-04-01 and last updated on 2026-06-17.
References
- https://github.com/ggml-org/llama.cpp/commit/39bf0d3c6a95803e0f41aaba069ffbee26721042
- https://github.com/ggml-org/llama.cpp/pull/20908
- https://github.com/ggml-org/llama.cpp/security/advisories/GHSA-j8rj-fmpv-wcxw
Affected products (1)
- cpe:2.3:a:ggml:llama.cpp:*:*:*:*:*:*:*:*
More vulnerabilities in Ggml Llama.cpp
- CVE-2024-42479 — Critical (CVSS 10.0): llama.cpp provides LLM inference in C/C++. The unsafe `data` pointer member in the `rpc_tensor` structure can cause…
- CVE-2026-21869 — High (CVSS 8.8): llama.cpp is an inference of several LLM models in C/C++. In commits 55d4206c8 and prior, the n_discard parameter is…
- CVE-2025-49847 — High (CVSS 8.8): llama.cpp is an inference of several LLM models in C/C++. Prior to version b5662, an attacker‐supplied GGUF model…
- CVE-2024-23605 — High (CVSS 8.8): A heap-based buffer overflow vulnerability exists in the GGUF library header.n_kv functionality of llama.cpp Commit…
- CVE-2024-23496 — High (CVSS 8.8): A heap-based buffer overflow vulnerability exists in the GGUF library gguf_fread_str functionality of llama.cpp Commit…
- CVE-2024-21836 — High (CVSS 8.8): A heap-based buffer overflow vulnerability exists in the GGUF library header.n_tensors functionality of llama.cpp…
All CVEs affecting Ggml Llama.cpp →
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