CVE-2026-66750

Description

Let's Chat 0.3.0 through 0.4.8 contains a broken access control vulnerability that allows authenticated attackers to download file attachments from private and password-protected rooms they are not a member of by exploiting missing room membership checks in the file retrieval route. Attackers can enumerate adjacent MongoDB ObjectIds derived from a known file ID to recover files uploaded by other users, as the GET /files/:id/:name route in app/controllers/files.js only enforces login authentication without consulting room membership or the Room.canJoin check.

CVSS Vector

References

• https://github.com/theopaid/Insufficient-Access-Controls-Allow-for-Unauthorized-File-Downloads-Let-s-Chat-
• https://www.vulncheck.com/advisories/let-s-chat-broken-access-control-file-disclosure-via-get-files-route