Review reviewHigh

CVE-2026-55759

RocketChat Rocket.Chat

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 vulnera...

CVSS: 7.4
EPSS: 0.24%
CISA KEV: Not listed
Published: 2026.06.25

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.24%

Technical severityCVSS 7.4

Vulnerability overview

Affected product and versions

Product: RocketChat Rocket.Chat
Affected versions: >= 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
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that RocketChat Rocket.Chat and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE: CWE-287, CWE-294