CVE-2026-63398

Coop is an open source review and moderation tool from ROOST. Prior to 1.0.2, the SAML strategy's verify callback resolved the authenticated user by email alone using `kyselyUserFindByEmail`, without binding the lookup to the organization in `/saml/login/:orgId/callback`. An attacker who administers an organization and controls its SAML IdP signing key can submit an assertion for a victim email to another organization's callback when that target organization has registered the same signing certificate. The assertion verifies against the target certificate, and the email resolves to the target user, creating a session as that user and allowing full cross-tenant account takeover without privileges in the target organization. Exploitation requires the unusual configuration in which the target certificate matches a signing key controlled by the attacker. This issue is fixed in version 1.0.2.

CVSS

No CVSS.

References

Link	Resource
https://github.com/roostorg/coop/commit/d1be81b6b33abc1162ee6b9952d4bd1ca761b071
https://github.com/roostorg/coop/pull/783
https://github.com/roostorg/coop/releases/tag/1.0.2
https://github.com/roostorg/coop/security/advisories/GHSA-2v93-383c-9fw2

Configurations

No configuration.

History

30 Oct 2026, 23:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-30 23:17

Updated : 2026-10-30 23:17

NVD link : CVE-2026-63398

Mitre link : CVE-2026-63398

CVE.ORG link : CVE-2026-63398

JSON object : View

Products Affected

No product.

CWE

CWE-287

Improper Authentication

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