# CVE-2026-21869: llama.cpp: llama.cpp is an inference of several LLM models in C/C++

CVE-2026-21869 is fixed in llama.cpp on 1 platform by DEBIAN-CVE-2026-21869 (version 7593+dfsg-1), released January 8, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-21869
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0053
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jan 8, 2026

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | llama.cpp Debian 14 | 7593+dfsg-1 | [DEBIAN-CVE-2026-21869](https://patchblox.com/security/data/fix/linux/debian-cve-2026-21869.md) | Jan 8, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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