Cipher disclosure via unchecked partial-update identifier
Published Mar 4, 2026 · Updated Mar 4, 2026
Authorization bypass in Vaultwarden before 1.35.4 allows remote authenticated users to read another user’s cipher data. The put_cipher_partial handler retrieves the caller-supplied cipher identifier but omits ownership and access checks before serializing the cipher with to_json. Any regular account can expose another user’s encrypted cipher fields and attachment download URLs and can create unauthorized favorite or folder associations.
Summary
What happened
Authorization bypass in Vaultwarden before 1.35.4 allows remote authenticated users to read another user’s cipher data. The put_cipher_partial handler retrieves the caller-supplied cipher identifier but omits ownership and access checks before serializing the cipher with to_json. Any regular account can expose another user’s encrypted cipher fields and attachment download URLs and can create unauthorized favorite or folder associations.
The record
- CVE
- CVE-2026-27898
- Published
- Mar 4, 2026
- Updated
- Mar 4, 2026
- Vendor
- Dani Garcia
- Product
- Vaultwarden
- Classifications
- CWE-639, T1555.005
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 4, 2026CVE publishedPublication date reported by the CVE source.
- Mar 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 1.35.4
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.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo