CVE-2026-21869
CVE-2026-21869 · llama.cpp has Out-of-bounds Write in llama-server
This page contains facts from public vulnerability sources. Check the original advisory before updating.
llama.cpp is an inference of several LLM models in C/C++. In commits 55d4206c8 and prior, the n_discard parameter is parsed directly from JSON input in the llama.cpp server's completion endpoints without validation to ensure it's non-negative. When a negative value is supplied and the context fills up, llama_memory_seq_rm/add receives a reversed range and negative offset, causing out-of-bounds memory writes in the token evaluation loop. This deterministic memory corruption can crash the process or enable remote code execution (RCE). There is no fix at the time of publication.
CVSS 8.8 · High · EPSS 0.5% · Fix available
- Published
- Updated
Stack: system
Affected products and versions
llama.cpp
- Versions
- <= 55d4206c8: Affected
No fix published
llama.cpp Debian:14
- Versions
- 5151+dfsg-1~exp2
- 5151+dfsg-1~exp3
- 5318+dfsg-1
- 5318+dfsg-2
- 5713+dfsg-1
- 5760+dfsg-1
- 5760+dfsg-2
- 5760+dfsg-3
- 5760+dfsg-4
- 5882+dfsg-1
- 5882+dfsg-2
- 5882+dfsg-3
- 5882+dfsg-3~exp1
- 5882+dfsg-3~exp2
- 5882+dfsg-3~exp3
- 5882+dfsg-4
- 6641+dfsg-1
- 6641+dfsg-2
- 6641+dfsg-3
- Affected ranges
- ECOSYSTEM: < 7593+dfsg-1
Update to 7593+dfsg-1
llama.cpp Ubuntu:25.10
- Versions
- 5318+dfsg-1
- 5318+dfsg-2
- 5713+dfsg-1
- 5760+dfsg-1
- 5760+dfsg-3
- 5760+dfsg-4
- 5882+dfsg-2
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
llama.cpp Ubuntu:26.10
- Versions
- 8681+dfsg-1
- 9721+dfsg-1ubuntu1
- 10438+dfsg-1
- 10438+dfsg-1ubuntu1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published
llama.cpp Ubuntu:26.04:LTS
- Versions
- 5882+dfsg-2
- 8064+dfsg-1ubuntu1
- 8681+dfsg-1
- Affected ranges
- ECOSYSTEM: (−∞, +∞)
No fix published