CVE-2026-43631 PUBLISHED

llama.cpp b7492–b9060 Use-After-Free RCE via llama-server

Assigner: VulnCheck
Reserved: 01.05.2026 Published: 06.08.2026 Updated: 07.08.2026

llama.cpp builds b7492 through the latest b9060 contains a use-after-free vulnerability in the vocab pointer of llama-server when the --sleep-idle-seconds feature is enabled, allowing unauthenticated remote attackers to execute arbitrary code. Attackers can trigger the vulnerability by sending requests to affected endpoints while the server transitions to sleep mode, causing concurrent worker threads to dereference a freed vocab pointer that can be reclaimed with attacker-controlled data to achieve remote code execution.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 9.2

Product Status

Vendor ggml-org
Product llama.cpp
Versions Default: affected
  • affected from b7492 to b9060 (incl.)

Credits

  • Vladimir Tokarev (@G1ND1L4) - Vulnerability Research Tech Lead, Cyera finder
  • Ofek Itach (@ofekitach) - Security Research Team Lead, Cyera finder

References

Problem Types

  • CWE-416 Use After Free CWE
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') CWE