CVE-2026-45691

Nextcloud: Bypass of second factor authentication on DAV endpoints

CVSS 5.9 MEDIUMEPSS 0.3%CWE-287

Vexday Risk Score

13Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 5.9EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

01 Jun 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

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

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

Affected products

nextcloud · security-advisories

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References

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-mp6x-g55j-w9jw https://github.com/nextcloud/server/pull/59758 https://hackerone.com/reports/3573399