Vulnerability · Published Feb 6, 2026 · Assigned by VulDB
CVE-2026-2069ggml-org llama.cpp GBNF Grammar llama-grammar.cpp llama_grammar_advance_stack stack-based overflow
Low 3.3
In plain English
A low-severity stack buffer overflow in llama.cpp from ggml-org. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 4% of all known vulnerabilities).
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:14 | llama.cpp | no fix listed | DEBIAN-CVE-2026-2069 |
| Ubuntu:25.10 | llama.cpp | no fix listed | UBUNTU-CVE-2026-2069 |
| Ubuntu:26.04:LTS | llama.cpp | no fix listed | UBUNTU-CVE-2026-2069 |
| Ubuntu:26.10 | llama.cpp | no fix listed | UBUNTU-CVE-2026-2069 |
Affected products (as reported)
Weakness: CWE-121, CWE-119 · Vector: 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
References
- VDB-344636 | ggml-org llama.cpp GBNF Grammar llama-grammar.cpp llama_grammar_advance_stack stack-based overflow vdb-entry, technical-description
- VDB-344636 | CTI Indicators (IOB, IOC, IOA) signature, permissions-required
- Submit #745263 | llama.cpp commit 55abc39 Stack-based Buffer Overflow third-party-advisory
- https://github.com/ggml-org/llama.cpp/issues/18988 issue-tracking
- https://github.com/ggml-org/llama.cpp/issues/18988#event-4426704865 issue-tracking
- https://github.com/user-attachments/files/24761101/poc.zip exploit
- https://github.com/ggml-org/llama.cpp/pull/18993 issue-tracking, patch
- https://github.com/ggml-org/llama.cpp/ product