Auth bypass in Microsoft Simplechat
CVE-2026-57205
SimpleChat is a secure AI conversation application with personal and group workspaces for document-grounded interactions. Prior to 0.241.203, the authenticated GET /api/user/info/<user_id> and GET /api/user/profile-image/<user_id> endpoints in application/single_app/route_backend_users.py accepted a caller-supplied user_id and read the matching Cosmos DB user-settings document without object-level authorization, allowing a low-privilege authenticated user to retrieve another user's email address, display name, and profile image. This issue is fixed in version 0.241.203.
Vulnerability class: Information Disclosure
EPSS: 0.009 (57.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N.
Affected products
- Microsoft Simplechat — versions < 0.241.203
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM)
- security-advisories@github.com (x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-57205?
- CVE-2026-57205 is a medium-severity vulnerability in Microsoft Simplechat, classified under Information Disclosure. CVSS score: 4.3/10. Published 2026-07-16.
- How severe is CVE-2026-57205?
- Medium severity. CVSS v3 base score is 4.3 out of 10.