Buffer overflow in Ggml Llama.cpp
CVE-2026-27940
llama.cpp is an inference of several LLM models in C/C++. Prior to b8146, the gguf_init_from_file_impl() in gguf.cpp is vulnerable to an Integer overflow, leading to an undersized heap allocation. Using the subsequent fread() writes 528+ bytes of attacker-controlled data past the buffer boundary. This is a bypass of a similar bug in the same file - CVE-2025-53630, but the fix overlooked some areas. This vulnerability is fixed in b8146.
Vulnerability class: Buffer Overflow
EPSS: 0.002 (7.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
Affected products
- Ggml Llama.cpp
- Ggml-org Llama.cpp — versions < b8146
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-27940?
- CVE-2026-27940 is a high-severity vulnerability in Ggml Llama.cpp, classified under Heap-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-03-12.
- How severe is CVE-2026-27940?
- High severity. CVSS v3 base score is 7.8 out of 10.
- Is CVE-2026-27940 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.