CVE-2026-55759 Rocket.Chat: Apple Sign-In skips JWT claims validation, allowing expired and cross-audience token replay
Attackers can replay expired or cross-audience Apple identity tokens to authenticate as users due to missing JWT claims validation in Rocket.Chat.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-55759?
CVE-2026-55759 is a high-severity authentication bypass vulnerability in RocketChat Rocket.Chat, published on 24 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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, Rocket.Chat's Apple Sign-In handler verifies JWT signatures but skips claims validation. Any Apple-signed JWT with a non-empty iss is accepted regardless of aud, exp, nbf, or nonce. An attacker who obtains a target user's Apple identity token (from server logs, an intercepted sign-in flow, or another application sharing the same Apple developer team) can replay it to authenticate as that user, with no expiration on the replay window. 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.
Which versions are affected by CVE-2026-55759?
How do I fix CVE-2026-55759?
No fix has been published for CVE-2026-55759 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-55759 being exploited?
There is no known exploitation of CVE-2026-55759 in the wild and no public exploit code.
Sources
Also known as GHSA-c75c-5hc7-j4vp.