CVE-2026-21869
Last modified
CVE-2026-21869 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. 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. EPSS estimates a 0.44% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Ggml | Llama.Cpp | All versions |
References
- https://github.com/ggml-org/llama.cpp/security/advisories/GHSA-8947-pfff-2f3cExploit, Vendor Advisory
- https://github.com/ggml-org/llama.cpp/security/advisories/GHSA-8947-pfff-2f3cExploit, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
Frequently Asked Questions
What is CVE-2026-21869?
How severe is CVE-2026-21869?
How do I fix CVE-2026-21869?
How Strix Helps
- How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
- Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
- PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
- AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.
Related CVEs from 2026
- CVE-2026-21863Valkey is a distributed key-value database. Prior to version…7.5
- CVE-2026-21864Valkey-Bloom is a Rust based Valkey module which brings a Bl…7.5
- CVE-2026-21865Discourse is an open source discussion platform. In versions…6.5
- CVE-2026-21866Dify is an open-source LLM app development platform. Prior t…5.4
- CVE-2026-21867Rejected reason: Reason: This candidate was issued in error.
- CVE-2026-21868Flag Forge is a Capture The Flag (CTF) platform. Versions 2.…7.5
- CVE-2026-2187A vulnerability was found in Tenda RX3 16.03.13.11. The affe…8.8
- CVE-2026-21870BACnet Protocol Stack library provides a BACnet application …5.5
- CVE-2026-21871NiceGUI is a Python-based UI framework. From versions 2.13.0…6.1
- CVE-2026-21872NiceGUI is a Python-based UI framework. From versions 2.22.0…6.1
- CVE-2026-21873NiceGUI is a Python-based UI framework. From versions 2.22.0…6.1
- CVE-2026-21874NiceGUI is a Python-based UI framework. From versions v2.10.…5.3
Are you affected by CVE-2026-21869?
Run a free Strix scan to check your systems for this vulnerability.
Scan your code nowSource: NVD / NIST