CVE-2025-52566
CVE-2025-52566 is a high-severity vulnerability in Ggml Llama.cpp with a CVSS 3.x base score of 8.6. 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: High (CVSS 3.x base score 8.6)
- EPSS exploit prediction: 0% (24th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-19074
- 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 b5721, there is a signed vs. unsigned integer overflow in llama.cpp's tokenizer implementation (llama_vocab::tokenize) (src/llama-vocab.cpp:3036) resulting in unintended behavior in tokens copying size comparison. Allowing heap-overflowing llama.cpp inferencing engine with carefully manipulated text input during tokenization process. This issue has been patched in version b5721.
Frequently asked questions
- What is CVE-2025-52566?
- llama.cpp is an inference of several LLM models in C/C++. Prior to version b5721, there is a signed vs. unsigned integer overflow in llama.cpp's tokenizer implementation (llama_vocab::tokenize) (src/llama-vocab.cpp:3036) resulting in unintended behavior in tokens copying size comparison. Allowing heap-overflowing llama.cpp inferencing engine with carefully manipulated text input during tokenization process. This issue has been patched in version b5721.
- How severe is CVE-2025-52566?
- CVE-2025-52566 has a CVSS 3.x base score of 8.6, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2025-52566 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (24th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2025-52566?
- CVE-2025-52566 affects Ggml Llama.cpp. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2025-52566?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2025-52566 have an EU (EUVD) identifier?
- Yes. CVE-2025-52566 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19074.
- When was CVE-2025-52566 published?
- CVE-2025-52566 was published on 2025-06-24 and last updated on 2026-06-17.
References
- https://github.com/ggml-org/llama.cpp/commit/dd6e6d0b6a4bbe3ebfc931d1eb14db2f2b1d70af
- https://github.com/ggml-org/llama.cpp/security/advisories/GHSA-7rxv-5jhh-j6xx
Affected products (1)
- cpe:2.3:a:ggml:llama.cpp:*:*:*:*:*:*:*:*
More vulnerabilities in Ggml Llama.cpp
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- 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…
All CVEs affecting Ggml Llama.cpp →
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