CVE-2026-55176 Soft Machine: Cross-tenant workspace API auth bypass via shared `CONTAINER_SHARED_SECRET` bearer token
Attackers can bypass authentication using a shared secret to access and modify other tenants' workspaces in the Soft Machine cloud environment.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-55176?
CVE-2026-55176 is a critical authentication bypass vulnerability in Soft-Machine-io security, published on 30 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Soft Machine is a Virtual Machine–based agentic development environment / Cloud OS. In versions 0.2.247 and prior, two authentication helpers in /app/server.js — verifyContainerAuth() and authenticateWorkspaceHttp() — accept the global CONTAINER_SHARED_SECRET as a bearer token without verifying which workspace the caller belongs to. Because that secret is set identically on every container in the Fly app and is reachable from the user-facing process environment inside each workspace, any tenant can use it to authenticate to any other tenant's workspace API. The result is cross-workspace read, write, and destructive-restore primitives reachable from any paying customer's shell. The existing per-workspace token check (workspaceTokenMatches) protects the user-facing per-workspace token path, but the shared-secret bearer path bypasses it entirely. At time of publication, there are no publicly known patches.
Weakness: CWE-863
Which versions are affected by CVE-2026-55176?
How do I fix CVE-2026-55176?
No fix has been published for CVE-2026-55176 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-55176 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55176 exists.