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5.9
CVE-2026-45691: Nextcloud allows file access without completing two-factor login
CVE-2026-45691 · published 5 months ago
Summary
Versions of Nextcloud Server from 32.0.0 up to 32.0.8 and 33.0.0 up to 33.0.2 let a user who has only entered a password reuse a session cookie to read or change files, skipping the required second authentication step. This could let an attacker who obtains that cookie access your documents. Update Nextcloud Server to version 32.0.9 or later (or the matching Enterprise release) to close the gap.
What to do
- Update nextcloud to version 33.0.3.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Bitnami | – | nextcloud |
>= 33.0.0, < 33.0.3 Fix: upgrade to 33.0.3
|
| – | nextcloud | nextcloud_server |
>= 32.0.0, < 32.0.9 >= 33.0.0, < 33.0.3 >= 29.0.0, < 29.0.16.16 >= 30.0.0, < 30.0.17.9 >= 31.0.0, < 31.0.14.5 cpe:2.3:a:nextcloud:nextcloud_server:*:*:*:*:-:*:*:* |
Original advisory text
Nextcloud: Bypass of second factor authentication on DAV endpoints
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
References
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45691... Vendor Advisory
- https://hackerone.com/reports/3573399 URL
- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-mp6x-g... Vendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-45691 Vendor Advisory
- https://github.com/nextcloud/server/pull/59758 Patch
Internet-facing
60 days
Internal
At next upgrade
- Not known to be exploited
- Needs hands-on effort to exploit
- Gives an attacker partial control
Type
CWE-287Improper Authentication
Timeline
Published1 Jun 2026
Updated3 Nov 2026
First seen1 Jun 2026
Sources
GHSA-mp6x-g55j-w9jw · GHSA
CVE-2026-45691 · OSV
CVE-2026-45691 · NVD
BIT-nextcloud-2026-45691 · OSV
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