Description
Zulip is an open-source team collaboration tool. In Zulip Server versions through 12.1, GenericOpenIdConnectBackend matches the identity provider email claim to an active account's delivery_email without rejecting an explicitly false email_verified claim. If a configured identity provider returns an email address that the authenticating user does not control together with email_verified=false, Zulip can log the user into the existing account for that address. Exploitation requires a misconfigured trusted identity provider, and deployments whose authoritative identity provider only emits email addresses controlled by the authenticating user are not affected. This issue is fixed in version 12.2.
Published: 2026-10-14
Score: 9.1 Critical
EPSS: < 1% Very Low
KEV: No
AI Analysis

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Remediation

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History

Fri, 23 Oct 2026 00:45:00 +0000

Type Values Removed Values Added
First Time appeared Zulip
Zulip zulip
Vendors & Products Zulip
Zulip zulip

Thu, 15 Oct 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 14 Oct 2026 16:00:00 +0000

Type Values Removed Values Added
Description Zulip is an open-source team collaboration tool. In Zulip Server versions through 12.1, GenericOpenIdConnectBackend matches the identity provider email claim to an active account's delivery_email without rejecting an explicitly false email_verified claim. If a configured identity provider returns an email address that the authenticating user does not control together with email_verified=false, Zulip can log the user into the existing account for that address. Exploitation requires a misconfigured trusted identity provider, and deployments whose authoritative identity provider only emits email addresses controlled by the authenticating user are not affected. This issue is fixed in version 12.2.
Title Zulip: OpenID Connect authentication ignores the email_verified claim
Weaknesses CWE-287
References
Metrics cvssV4_0

{'score': 9.1, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-15T19:06:20.918Z

Reserved: 2026-09-29T17:34:42.743Z

Link: CVE-2026-102893

cve-icon Vulnrichment

Updated: 2026-10-15T19:06:07.115Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-14T16:17:29.987

Modified: 2026-10-16T20:02:37.630

Link: CVE-2026-102893

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-22T22:15:12Z

Weaknesses