CVE-2026-2069 PUBLISHED

A flaw has been found in ggml-org llama.cpp up to 55abc39. Impacted is the function llama_grammar_advance_stack of the file llama.cpp/src/llama-grammar.cpp of the component GBNF Grammar Handler. This manipulation causes stack-based buffer overflow. The attack needs to be launched locally. The exploit has been published and may be used. Patch name: 18993. To fix this issue, it is recommended to deploy a patch.

• TYGLS (VulDB User) reporter

• VDB-344636 | ggml-org llama.cpp GBNF Grammar llama-grammar.cpp llama_grammar_advance_stack stack-based overflow
• VDB-344636 | CTI Indicators (IOB, IOC, IOA)
• Submit #745263 | llama.cpp commit 55abc39 Stack-based Buffer Overflow
• https://github.com/ggml-org/llama.cpp/issues/18988
• https://github.com/ggml-org/llama.cpp/issues/18988#event-4426704865
• https://github.com/user-attachments/files/24761101/poc.zip
• https://github.com/ggml-org/llama.cpp/pull/18993
• https://github.com/ggml-org/llama.cpp/

• Stack-based Buffer Overflow CWE
• Memory Corruption CWE