CVE-2026-45691

Nextcloud: Bypass of second factor authentication on DAV endpoints

MEDIUM

5.9

CVSS Score

Published: June 1, 2026 at 05:09 PM UTC

Updated: July 22, 2026 at 08:27 AM UTC

1 product affected across 1 vendorNextcloud/server

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Severity

MEDIUM5.9

Exploit prediction

EPSS 0.3%

SSVC

No known exploit

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

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Nextcloud/server · Nextcloudnextcloud-app

95%

29.0.0 ≤ v < 29.0.16.1630.0.0 ≤ v < 30.0.17.931.0.0 ≤ v < 31.0.14.532.0.0 ≤ v < 32.0.933.0.0 ≤ v < 33.0.3

Affected range stops below 29.0.16.16, so it looks safe — our inference, not a vendor statement

Affected range stops below 30.0.17.9, so it looks safe — our inference, not a vendor statement

Affected range stops below 31.0.14.5, so it looks safe — our inference, not a vendor statement

Affected range stops below 32.0.9, so it looks safe — our inference, not a vendor statement

Affected range stops below 33.0.3, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

x_refsource_CONFIRMVendor Advisory

Source: cverecord

https://github.com/nextcloud/security-advisories/security/advisories/GHSA-mp6x-g55j-w9jw

x_refsource_MISCIssue TrackingPatch

Source: cverecord

https://github.com/nextcloud/server/pull/59758

x_refsource_MISCPermissions Required

Source: cverecord

https://hackerone.com/reports/3573399

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMGitHub_M

Attack Vector: NETWORK
Complexity: HIGH
Privileges: LOW
User Interaction: NONE
Scope: UNCHANGED
Confidentiality: LOW
Integrity: HIGH
Availability: NONE

Vector?

Quick Info

StatusANALYZED

CWE

CWE-287

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