CVE-2026-45691: Nextcloud Server

Medium severity, CVSS 5.9. EPSS: 0.4% chance of exploitation in the next 30 days.

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

Affected products

• Nextcloud Nextcloud Server: from 32.0.0, before 32.0.9 (fixed in 32.0.9); from 33.0.0, before 33.0.3 (fixed in 33.0.3); from 29.0.0, before 29.0.16.16 (fixed in 29.0.16.16); from 30.0.0, before 30.0.17.9 (fixed in 30.0.17.9); from 31.0.0, before 31.0.14.5 (fixed in 31.0.14.5)

Published 2026-06-01. Last modified 2026-07-22.