{"identifier":"CVE-2026-102893","cve":{"id":"CVE-2026-102893","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":"2026-10-14T16:17:29.987000+00:00","modified":"2026-10-16T20:02:37.630000+00:00","status":"Awaiting Analysis","score":9.1,"severity":"CRITICAL","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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_version":"4.0","affected":[],"weaknesses":["CWE-287"],"references":[{"url":"https://github.com/zulip/zulip/commit/68d2d9defa39f8af96a50fc7430efc34dee120b5","source":"security-advisories@github.com"},{"url":"https://github.com/zulip/zulip/commit/b40f191a8c71e74fcb471f71de6a1233de157102","source":"security-advisories@github.com"},{"url":"https://github.com/zulip/zulip/pull/39913","source":"security-advisories@github.com"},{"url":"https://github.com/zulip/zulip/releases/tag/12.2","source":"security-advisories@github.com"},{"url":"https://github.com/zulip/zulip/security/advisories/GHSA-xw9h-9rcm-hx4m","source":"security-advisories@github.com"}],"kev":null,"kev_checked":true,"metrics":{"cvssMetricV40":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"4.0","vectorString":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":9.1,"baseSeverity":"CRITICAL","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-10-15T19:05:46.384884Z","id":"CVE-2026-102893","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[],"source":"nvd","retrieved_at":"2026-10-28T10:22:18.240837+00:00","exploited":false,"kev_stale":false,"products":[],"priority":{"label":"Critical technical severity","reasons":["CVSS is at least 9.0; exploitation is not established by severity alone."]},"epss":{"probability":0.0039,"percentile":0.33026,"date":"2026-10-29","stale":false},"version_assessment":null},"news":[],"campaigns":[],"domains":[{"domain":"github.com","source_url":"https://github.com/zulip/zulip/commit/68d2d9defa39f8af96a50fc7430efc34dee120b5","investigate_url":"https://investigate.aeglixmind.com/#github.com"}],"arsenal_url":"https://arsenal.aeglixmind.com/?cve=CVE-2026-102893","catalog_url":"https://cves.aeglixmind.com/cve/CVE-2026-102893","research_url":"https://investigate.aeglixmind.com/research/cve/CVE-2026-102893","coverage":{"news_candidates_checked":0,"campaign_candidates_checked":0,"bounded":false,"notice":"Exact CVE mentions in stored public excerpts and reviewed campaign content only. A mention is not proof of exploitation, attribution or tool suitability. Missing matches do not establish absence."}}