Vulnerability · Published Jun 24, 2026 · Assigned by GitHub_M
CVE-2026-55666Rocket.Chat: Email Parameter Fallback Leads To Account Takeover Within Apple OAuth
Critical 9.3
In plain English
A critical-severity improper authentication in Rocket.Chat from RocketChat. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities).
Official description
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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| RocketChat | Rocket.Chat | >= 8.5.0-rc.0, < 8.5.1>= 8.4.0-rc.0, < 8.4.4>= 8.3.0-rc.0, < 8.3.6>= 8.2.0-rc.0, < 8.2.6>= 8.1.0-rc.0, < 8.1.6>= 7.11.0-rc.0, < 8.0.7< 7.10.13 |
Weakness: CWE-287, CWE-288 · 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