Home

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.

PUBLISHED Reserved 2026-01-05 | Published 2026-01-07 | Updated 2026-01-08 | Assigner GitHub_M




HIGH: 8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Problem types

CWE-787: Out-of-bounds Write

Product status

<= 55d4206c8
affected

References

github.com/...ma.cpp/security/advisories/GHSA-8947-pfff-2f3c exploit

github.com/...ma.cpp/security/advisories/GHSA-8947-pfff-2f3c

cve.org (CVE-2026-21869)

nvd.nist.gov (CVE-2026-21869)

Download JSON