What’s Vulnerable › Vulnerabilities

CVE-2026-66750: Let's Chat 0.3.0 - 0.4.8 Broken Access Control File Disclosure via GET /files route

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-28 · updated 2026-10-24
• Weakness: CWE-862

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.

Affected products

• sdelements lets-chat: from 0.3.0 through 0.4.8

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

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