Critical severity · published Sep 30, 2026
CVE-2026-55176
Soft Machine: Cross-tenant workspace API auth bypass via shared `CONTAINER_SHARED_SECRET` bearer token
9.0
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack vector
Adjacent
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 21% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SE
security · Soft-Machine-io
<= 0.2.247 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55176
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-55176
x_refsource_CONFIRM
https://github.com/Soft-Machine-io/security/security/advisories/GHSA-63gh-vp9f-vxhj
More from security
8.3
CVE-2026-46711
Soft Machine: Unauthenticated workspace API exposes arbitrary file read & directory exfiltration to any peer on the Fly private network
