CVE-2026-55666 PUBLISHED

Rocket.Chat: Email Parameter Fallback Leads To Account Takeover Within Apple OAuth

Assigner: GitHub_M
Reserved: 17.06.2026 Published: 24.06.2026 Updated: 24.06.2026

Rocket.Chat is an open-source, secure, fully customizable communications platform. Prior to 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13, in apps/meteor/app/apple/server/loginHandler.ts, handleIdentityToken parses a JWT issued by Apple during the OAuth flow. The try block checks for an email parameter. If the JWT does not contain an email address, the application falls back to accepting an arbitrary email value supplied directly in the request. Attackers are able to forge Apple JWTs that do not contain an email address and leverage this vulnerability to carry out account takeover attacks. This vulnerability is fixed in 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, and 7.10.13.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 9.3

Product Status

Vendor RocketChat
Product Rocket.Chat
Versions
  • Version >= 8.5.0-rc.0, < 8.5.1 is affected
  • Version >= 8.4.0-rc.0, < 8.4.4 is affected
  • Version >= 8.3.0-rc.0, < 8.3.6 is affected
  • Version >= 8.2.0-rc.0, < 8.2.6 is affected
  • Version >= 8.1.0-rc.0, < 8.1.6 is affected
  • Version >= 7.11.0-rc.0, < 8.0.7 is affected
  • Version < 7.10.13 is affected

References

Problem Types

  • CWE-287: Improper Authentication CWE
  • CWE-288: Authentication Bypass Using an Alternate Path or Channel CWE