CVE-2026-45691 MEDIUM

CVE-2026-45691: Nextcloud: Bypass of second factor authentication on DAV endpoints

Vendor Nextcloud
Product security-advisories
Weakness CWE-287 · Improper authentication
Published June 1, 2026
Last update June 1, 2026

CVSS base score

5.9/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Confidentiality Low
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N

What the vulnerability does

01Description

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

Key dates

02Disclosure timeline

June 1, 2026 CVE published
June 1, 2026 Record updated