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CVE-2026-45690

Nextcloud: Two-Factor Authentication Bypass via Pending Session Token Replay

Published: Jun 1, 2026Updated: Jun 1, 2026 Sources: CVE List NVD
NVD MITRE
5.9CVSS
MEDIUM

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

EPSS Score
N/A
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

CVSS Vector Breakdown

AV:NAC:HPR:LUI:NS:UC:LI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:HIntegrity
High
A:NAvailability
None

Weaknesses

CWE-287

Affected Products

security-advisories
nextcloud

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

2 techniques
Initial Access
View detailed technique mapping

References

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

Timeline

Published
Jun 1, 2026
Last Updated
Jun 1, 2026

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