Use-After-Free Vulnerability in llama.cpp RPC Server
CVE-2026-39909

9.2CRITICAL

Key Information:

Vendor

Ggml-org

Status
Llama.cpp
Vendor
CVE Published:
21 August 2026

What is CVE-2026-39909?

A use-after-free vulnerability exists in the RPC server's GRAPH_RECOMPUTE handler of llama.cpp prior to version b8585. This flaw allows unauthorized remote attackers to execute arbitrary read and write operations. By manipulating computation graphs, attackers can free referenced buffers and later reclaim the freed memory, substituting it with malicious content. This exploitation enables the execution of arbitrary code remotely without requiring any form of authentication or user intervention, posing significant risks to the security of affected systems.

Affected Version(s)

llama.cpp 0

References

https://github.com/ggml-org/llama.cpp/releases/tag/b8585
release-notes
https://github.com/ggml-org/llama.cpp/pull/21175
issue-tracking
https://github.com/ggml-org/llama.cpp/commit/389c7d4955ba...
patch

CVSS V4

Score:
9.2
Severity:
CRITICAL
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
High
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Olivier Laflamme
.