CVE-2026-2069 ggml-org llama.cpp GBNF Grammar llama-grammar.cpp llama_grammar_advance_stack stack-based overflow
A local attacker can trigger a stack-based buffer overflow in the GBNF grammar handler of llama.cpp, potentially leading to code execution or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-2069?
CVE-2026-2069 is a medium-severity memory corruption vulnerability in ggml-org llama.cpp, published on 6 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.
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.
Which versions are affected by CVE-2026-2069?
How do I fix CVE-2026-2069?
No fix has been published for CVE-2026-2069 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-2069 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-2069 exists.
Sources
Also known as DEBIAN-CVE-2026-2069, GHSA-f8m3-93xm-637c, UBUNTU-CVE-2026-2069.