SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityDeferred

CVE-2026-55176

The existing per-workspace token check (workspaceTokenMatches) protects the user-facing per-workspace token path, but the shared-secret bearer path bypasses it entirely.

CRITICAL 9.0EPSS 0.29%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.29%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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 3.1
9.0 CRITICALCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS
0.29% probability · 21th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-863
Source
security-advisories@github.com
EPSS trend
0%3%5%1 October 2026: 0.32%26 October 2026: 0.29%1 October 202626 October 2026

EPSS moved from 0.3% on 1 October 2026 to 0.3% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.