Bug 2483834 (CVE-2026-45691) - CVE-2026-45691 nextcloud-server: Nextcloud Server: Two-factor authentication bypass via session cookie reuse
Summary: CVE-2026-45691 nextcloud-server: Nextcloud Server: Two-factor authentication ...
Keywords:
Status: NEW
Alias: CVE-2026-45691
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2483844 2483851
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-01 21:45 UTC by Jon Moroney
Modified: 2026-06-09 08:56 UTC (History)
0 users

Fixed In Version:
Clone Of:
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Description Jon Moroney 2026-06-01 21:45:57 UTC 
Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, a pre-2FA session cookie (created after successful password authentication but before TOTP completion) could be reused as a Bearer token to authenticate against DAV endpoints, granting read/write access and bypassing mandatory two-factor authentication. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9 or 29.0.16.16
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