CVE-2026-2069
ggml-org llama.cpp GBNF Grammar llama-grammar.cpp llama_grammar_advance_stack stack-based overflow
- State
- Published
- Severity
- 4.8 Medium
- Published
- Feb 6, 2026
- Updated
- Feb 23, 2026
- Reserved
- Feb 6, 2026
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 4.8 Medium | CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P | VulDB |
| 3.1 | 3.3 Low | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C | VulDB |
| 3.0 | 3.3 Low | CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C | VulDB |
| 2.0 | 1.7 Low | AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:OF/RC:C | VulDB |
Weaknesses
Affected Products
| Product | Versions |
|---|---|
llama.cppggml-org |
|
References
- VDB-344636 | ggml-org llama.cpp GBNF Grammar llama-grammar.cpp llama_grammar_advance_stack stack-based overflowvdb-entrytechnical-description
- VDB-344636 | CTI Indicators (IOB, IOC, IOA)signaturepermissions-required
- Submit #745263 | llama.cpp commit 55abc39 Stack-based Buffer Overflowthird-party-advisory
- https://github.com/ggml-org/llama.cpp/issues/18988issue-tracking
- https://github.com/ggml-org/llama.cpp/issues/18988#event-4426704865issue-tracking
- https://github.com/user-attachments/files/24761101/poc.zipexploit
- https://github.com/ggml-org/llama.cpp/pull/18993issue-trackingpatch
- https://github.com/ggml-org/llama.cpp/product
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