Bug 2447033 (CVE-2026-27940)

Summary: CVE-2026-27940 llama.cpp: heap-based buffer overflow via integer overflow in mem_size calculation (bypass of CVE-2025-53630 fix)
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in llama.cpp. A integer overflow can occur in the gguf_init_from_file_impl function in the gguf.cpp file, leading to an undersized heap allocation. A subsequent fread function call can write 528+ bytes of attacker controlled data past the buffer boundary. This issue is a bypass of CVE-2025-53630.
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Bug Depends On: 2448112    
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Description OSIDB Bzimport 2026-03-12 17:01:56 UTC 
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.