CVE-2026-55666CWE-287CWE-288

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

Critical · published June 24, 2026

CVSS v4.0
9.3
EPSS
0%
Percentile
33.7
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
9.3 · CRITICAL
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
EPSS
0.00406 · 33.7th percentile
Weaknesses
CWE-287 · Improper Authentication; CWE-288 · Authentication Bypass Using an Alternate Path or Channel
Published
2026-06-24T21:06Z
EPSS history
Timeline
  • 24 JUN 21:06Z
    Rocket.Chat: Email Parameter Fallback Leads To Account Takeover Within Apple OAuth
    cvelistv5