CVE-2026-102893 Zulip: OpenID Connect authentication ignores the email_verified claim
Attackers can hijack accounts if a misconfigured identity provider sends unverified emails, allowing login to existing accounts.
- 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-2026-102893?
CVE-2026-102893 is a critical authentication bypass vulnerability in zulip, published on 14 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-287
Which versions are affected by CVE-2026-102893?
How do I fix CVE-2026-102893?
No fix has been published for CVE-2026-102893 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-2026-102893 being exploited?
There is no known exploitation of CVE-2026-102893 in the wild and no public exploit code.
Sources
Also known as GHSA-xw9h-9rcm-hx4m.