Auth bypass in Nextcloud Nextcloud_server
CVE-2026-45691
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…
Vulnerability class: Broken Authentication
EPSS: 0.001 (17.4th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N.
Affected products
- Nextcloud Nextcloud_server
- Nextcloud Security-advisories — versions >= 32.0.0, < 32.0.9, >= 33.0.0, < 33.0.3
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Permissions Required, x_refsource_MISC)
Frequently asked questions
- What is CVE-2026-45691?
- CVE-2026-45691 is a medium-severity vulnerability in Nextcloud Nextcloud_server, classified under Improper Authentication. CVSS score: 5.9/10. Published 2026-06-01.
- How severe is CVE-2026-45691?
- Medium severity. CVSS v3 base score is 5.9 out of 10.