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CVE-2026-27898

Vaultwarden: Unauthorized Access via Partial Update API on Another User’s Cipher

Published: Mar 4, 2026Updated: Mar 5, 2026 Sources: CVE List NVD GHSACWE-639
NVD MITRE
5.4CVSSMEDIUM
EPSS Score
0.2%
Top 93.8%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

Vaultwarden is an unofficial Bitwarden compatible server written in Rust, formerly known as bitwarden_rs. Prior to version 1.35.4, an authenticated regular user can specify another user’s cipher_id and call "PUT /api/ciphers/{id}/partial" Even though the standard retrieval API correctly denies access to that cipher, the partial update endpoint returns 200 OK and exposes cipherDetails (including name, notes, data, secureNote, etc.). This issue has been patched in version 1.35.4.

CVSS Vector Breakdown

AV:NAC:LPR:LUI:NS:UC:LI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:LConfidentiality
Low
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-639

Affected Products

vaultwardencrates.ioOSS Libraries
vaultwardendani-garcia
On-prem
Security Products / identity-access-mgmt
crates.iopackage-ecosystemOSS Libraries
dani-garciaoss-projectSecurity Productsaka vaultwarden

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Initial Access
View detailed technique mapping

References

https://github.com/dani-garcia/vaultwarden/security/advisories/GHSA-w9f8-m526-h7fh
github.com
https://github.com/dani-garcia/vaultwarden
github.com

Timeline

Published
Mar 4, 2026
Last Updated
Mar 5, 2026

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