CVE-2026-45691 (GCVE-0-2026-45691)

Vulnerability from cvelistv5 – Published: 2026-06-01 17:09 – Updated: 2026-06-01 19:10
VLAI
Title
Nextcloud: Bypass of second factor authentication on DAV endpoints
Summary
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
Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-287 - Improper Authentication
Assigner
References
Impacted products
Vendor Product Version
nextcloud security-advisories Affected: >= 32.0.0, < 32.0.9
Affected: >= 33.0.0, < 33.0.3
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.