OIDC state bypass via mismatched-token disclosure
Published Apr 4, 2023 · Updated Feb 11, 2025
CSRF in Nextcloud user_oidc before 1.3.0 allows remote authenticated users to bypass OIDC state protection during login. The code handlers in LoginController and Id4meController returned the submitted state and the session's expected state when they differed, exposing the token needed to repeat the request. Exploitation requires high privileges and user interaction; the vendor does not specify the resulting data access or modification.
Summary
What happened
CSRF in Nextcloud user_oidc before 1.3.0 allows remote authenticated users to bypass OIDC state protection during login. The code handlers in LoginController and Id4meController returned the submitted state and the session's expected state when they differed, exposing the token needed to repeat the request. Exploitation requires high privileges and user interaction; the vendor does not specify the resulting data access or modification.
The record
- CVE
- CVE-2023-28848
- Published
- Apr 4, 2023
- Updated
- Feb 11, 2025
- Vendor
- Nextcloud GmbH
- Product
- Security Advisories
- Classifications
- CWE-352
- Attack vector
- network
- Privileges
- admin
Timeline
How it unfolded
- Apr 4, 2023CVE publishedPublication date reported by the CVE source.
- Feb 11, 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=>= 1.0.0, < 1.3.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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