Executive brief
Boxlite is a sandbox service used to create virtual machines and run untrusted code in isolated containers. A flaw in its timeout mechanism allows malicious code to ignore shutdown commands and continue running indefinitely. This can lead to resource exhaustion, potentially causing service outages or impacting the performance of other users on the same system.
Technical details
Boxlite versions 0.8.2 and prior contain a resource management vulnerability in the timeout watcher component (`src/guest/src/service/exec/timeout.rs`). When a user-configured execution timeout is reached, the service incorrectly issues a `SIGALRM` (signal 14) instead of a `SIGKILL` (signal 9). Because `SIGALRM` can be caught or ignored by the guest process (e.g., via `signal.SIG_IGN` in Python or `trap` in shell), malicious code can bypass the timeout and continue running. This leads to improper resource shutdown (CWE-404) and can result in denial-of-service through resource exhaustion. The issue has been patched in commit 28159fc by implementing a two-stage termination process (SIGTERM followed by a SIGKILL fallback).
Affected products
- boxlite-ai Boxlite <= 0.8.2
Timeline
- 2026-05-19: patched: Fix committed to repository and advisory published by vendor.
- 2026-06-10: disclosed: CVE published to NVD.