Second-factor bypass via misclassified session tokens
Published May 16, 2025 · Updated May 16, 2025
Improper authentication in affected Nextcloud Server and Enterprise Server releases allows remote authenticated users to bypass the second factor. The session setup code tests a token's remember property instead of its type, marking nonpermanent sessions as app passwords and preserving authentication after expiry. The bypass requires valid username and password credentials, a remember_login_cookie_lifetime value of 0, expiration on the second-factor page, and a reload; the session then receives the account's normal access without the required second factor.
Summary
What happened
Improper authentication in affected Nextcloud Server and Enterprise Server releases allows remote authenticated users to bypass the second factor. The session setup code tests a token's remember property instead of its type, marking nonpermanent sessions as app passwords and preserving authentication after expiry. The bypass requires valid username and password credentials, a remember_login_cookie_lifetime value of 0, expiration on the second-factor page, and a reload; the session then receives the account's normal access without the required second factor.
The record
- CVE
- CVE-2025-47790
- Published
- May 16, 2025
- Updated
- May 16, 2025
- Vendor
- Nextcloud GmbH
- Product
- Security Advisories
- Classifications
- CWE-287, T1078
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- May 16, 2025CVE publishedPublication date reported by the CVE source.
- May 16, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 26.0.0, < 26.0.13.15
- Affected versionversion=>= 27.0.0, < 27.1.11.15
- Affected versionversion=>= 28.0.0, < 28.0.14.6
- Affected versionversion=>= 29.0.0, < 29.0.15
- Affected versionversion=>= 30.0.0, < 30.0.9
- Affected versionversion=>= 31.0.0, < 31.0.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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