CVE-2026-2069: ggml-org llama.cpp GBNF Grammar llama-grammar.cpp llama_grammar_advance_stack stack-based overflow

Published Feb 6, 2026
·
Updated

A flaw has been found in ggml-org llama.cpp up to 55abc39. Impacted is the function llamagrammaradvancestack 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.

Affected Software

1 affected component
ggml-org/llama.cpp<=55abc39

Event History

Feb 6, 2026
CVE Published
via MITRE·10:02 PM
Data Sourced
via MITRE·10:02 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·10:16 PM
DescriptionSeverityWeakness
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Frequently Asked Questions

1

What is the severity of CVE-2026-2069?

CVE-2026-2069 has been classified as a high severity vulnerability due to its potential for stack-based buffer overflow, which can allow arbitrary code execution.

2

How do I fix CVE-2026-2069?

To resolve CVE-2026-2069, update your version of ggml-org llama.cpp to a version beyond 55abc39 where the vulnerability has been addressed.

3

Which components are affected by CVE-2026-2069?

CVE-2026-2069 affects the GBNF Grammar Handler in the llama_grammar_advance_stack function of the llama.cpp/src/llama-grammar.cpp file.

4

What are the exploitation conditions for CVE-2026-2069?

Exploitation of CVE-2026-2069 may require an attacker to send specially crafted inputs to the GBNF Grammar Handler, leading to potential unintentional execution of code.

5

Is CVE-2026-2069 present in all versions of ggml-org llama.cpp?

No, CVE-2026-2069 is only present in ggml-org llama.cpp versions up to and including 55abc39.

Contact

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