CVE-2026-47158

Deferred Deferred - Pending Action

Vaultwarden SSO Authentication Bypass via Unbound State Parameter

Publication date: 2026-07-15

Last updated on: 2026-07-15

Assigner: GitHub, Inc.

Description

Vaultwarden is a Bitwarden-compatible server written in Rust. Prior to 1.36.0, Vaultwarden's SSO authorization flow did not bind the OAuth state parameter accepted by /connect/authorize to the initiating browser session, allowed attacker-controlled PKCE parameters, and left SsoAuth records intact after failed token exchange, allowing an unauthenticated attacker to induce IdP authentication and redeem tokens for a fully authenticated session. This issue is fixed in version 1.36.0.

CVSS Scores

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Meta Information

Published

2026-07-15

Last Modified

2026-07-15

Generated

2026-08-05

AI Q&A

2026-07-16

EPSS Evaluated

2026-08-03

NVD

CVE-2026-47158

EUVD

EUVD-2026-44693

Affected Vendors & Products

Vendor	Product	Version / Range
dani-garcia	vaultwarden	1.36.0
dani-garcia	vaultwarden	to 1.35.8 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-352	The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.

Attack-Flow Graph

Executive Summary

CVE-2026-47158 is a vulnerability in Vaultwarden's SSO authorization flow that allowed unauthenticated attackers to hijack user sessions. The flaw involved three issues: the OAuth state parameter was not bound to the browser session, attacker-controlled PKCE parameters were allowed, and failed token exchanges left SsoAuth records intact. This enabled attackers to trick victims into completing IdP authentication and then redeem tokens for full account access.

Detection Guidance

Detecting this vulnerability requires checking if your Vaultwarden instance is running a vulnerable version (1.35.8 or earlier). Use commands like 'vaultwarden --version' or check your container tag if using Docker. Monitor logs for unusual SSO authentication attempts or failed token exchanges.

Impact Analysis

An attacker could trick you into completing an IdP authentication step, then use your session tokens to gain full access to your Vaultwarden account, including encrypted vault data. Even with two-factor authentication enabled, your account could be compromised. Attackers might also perform account squatting or disclose your user information.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection principles and HIPAA's security requirements for protected health information. Organizations using affected versions may face compliance breaches, legal liabilities, and reputational damage due to potential data exposure.

Mitigation Strategies

Upgrade Vaultwarden to version 1.36.0 or later immediately. Enable two-factor authentication for all SSO users. Restrict SSO to known domains and apply rate limits to SSO endpoints to prevent brute-force attacks.

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