{"id":"CVE-2026-102893","title":"Zulip is an open-source team collaboration tool","summary":"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 ema…","severity":"critical","cvss":9.1,"cvssVector":"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","cwe":["CWE-287"],"vendor":"zulip","product":"zulip","affected":["zulip < 12.2"],"published":"2026-10-14","updated":"2026-10-16","sourceUpdated":"2026-10-16T20:02:37.630","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-102893","references":[{"url":"https://github.com/zulip/zulip/commit/68d2d9defa39f8af96a50fc7430efc34dee120b5","label":"security-advisories@github.com"},{"url":"https://github.com/zulip/zulip/commit/b40f191a8c71e74fcb471f71de6a1233de157102","label":"security-advisories@github.com"},{"url":"https://github.com/zulip/zulip/pull/39913","label":"security-advisories@github.com"},{"url":"https://github.com/zulip/zulip/releases/tag/12.2","label":"security-advisories@github.com"},{"url":"https://github.com/zulip/zulip/security/advisories/GHSA-xw9h-9rcm-hx4m","label":"security-advisories@github.com"}],"tags":["nvd","cve.org"],"epss":0.0039,"epssPercentile":0.32895,"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-15T19:05:46.384884Z"},"cvssSource":"cna","ingestedAt":"2026-10-14T16:40:32.111Z","slug":"CVE-2026-102893","body":"## Overview\n\nZulip 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":221324,"id":"CVE-2026-102893","ts":1792031117609,"field":"cvss","old":null,"new":"9.1"},{"seq":221323,"id":"CVE-2026-102893","ts":1792031117609,"field":"severity","old":"none","new":"critical"}]}