CVE-2026-23520: critical vulnerability in getarcaneapp arcane

Arcane provides modern docker management. Prior to 1.13.0, Arcane has a command injection in the updater service. Arcane’s updater service supported lifecycle labels com.getarcaneapp.arcane.lifecycle.pre-update and com.getarcaneapp.arcane.lifecycle.post-update that allowed defining a command to run before or after a container update. The label value is passed directly to /bin/sh -c without sanitization or validation. Because any authenticated user (not limited to administrators) can create projects through the API, an attacker can create a project that specifies one of these lifecycle labels with a malicious command. When an administrator later triggers a container update (either manually or via scheduled update checks), Arcane reads the lifecycle label and executes its value as a shell command inside the container. This vulnerability is fixed in 1.13.0.