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TI-2026-40188 Aliases CVE-2026-55666

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

Priority MEDIUM 48CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-287.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00406 35th percentileScored 2026-11-07
Fix Fixed Rocket.Chat (RocketChat): 8.5.1, 8.4.4, 8.3.6 +4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
RocketChatRocket.Chat8.5.0-rc.0 to before 8.5.1; 8.4.0-rc.0 to before 8.4.4; 8.3.0-rc.0 to before 8.3.6; 8.2.0-rc.0 to before 8.2.6; 8.1.0-rc.0 to before 8.1.6; 7.11.0-rc.0 to before 8.0.7; before 7.10.138.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, 7.10.13Patch availableCNA
  • Rocket.Chat VendorRocketChat Affected 8.5.0-rc.0 to before 8.5.1; 8.4.0-rc.0 to before 8.4.4; 8.3.0-rc.0 to before 8.3.6; 8.2.0-rc.0 to before 8.2.6; 8.1.0-rc.0 to before 8.1.6; 7.11.0-rc.0 to before 8.0.7; before 7.10.13 Fixed in 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, 7.10.13 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:rocket.chat:rocket.chat:*:*:*:*:*:*:*:*——Rocket.Chat
  • cpe:2.3:a:rocket.chat:rocket.chat:*:*:*:*:*:*:*:* Versions — — ·Rocket.Chat

Remediation

  • Fix · CNA Rocket.Chat (RocketChat) Fixed in 8.5.1, 8.4.4, 8.3.6, 8.2.6, 8.1.6, 8.0.7, 7.10.13

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-55666

References

Other 1

  • TI-2026-33430 Rocket.Chat: Pre-Auth NoSQL Injection in CAS Login Handler leading to Arbitrary CAS/SAML User Session Hijack CVSS 3.1CRITICAL 9.1
  • TI-2026-33431 Rocket.Chat: Pre-Auth NoSQL Injection in OAuth2 Token Endpoint leading to Arbitrary User ATO CVSS 3.1CRITICAL 9.1
  • TI-2026-18910 Rocket.Chat Unauthorized Access to OAuth App Details CVSS 3.1HIGH 7.7
  • TI-2026-35234 Rocket.Chat: Missing URL protocol sanitization in ImageElement allows javascript: URLs in markdown images CVSS 3.1MEDIUM 4.4
  • TI-2026-22776 Rocket.Chat: Users can login with any password via the EE ddp-streamer-service CVSS 4.0CRITICAL 9.3
  • TI-2026-34135 Rocket.Chat: SAML signature validation skipped when IdP certificate field is empty CVSS 4.0CRITICAL 9.3
See all 20 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences