# CVE-2026-89022: BookStack social login authentication bypass

Source: https://junglewise.ai/threats/cve-2026-89022-bookstack-social-login-authentication-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-15. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-89022 · Severity: high · CVSS 7.4 · Published 2026-09-15

BookStack is a popular open-source documentation and knowledge management platform. A flaw in its social login feature allows attackers to sign in as arbitrary users without valid credentials by authenticating through a different social provider linked to the same account. This could grant unauthorized access to sensitive documents, settings, and user data across all BookStack instances using multiple social login methods.

## Quick answers

**Is CVE-2026-89022 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-89022 being exploited in the wild.

**How severe is CVE-2026-89022?** High severity, with a CVSS score of 7.4, published 15 September 2026.

**Which products and versions are affected?** BookStack BookStack before 26.05.5.

**Is there a fix for CVE-2026-89022?** A patch was published on 2026-09-14: Fix released in version 26.05.5 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-89022 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-89022?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

BookStack contains an authentication bypass vulnerability in the SocialAuthService::handleLoginCallback method, where user account lookups by social provider are not properly scoped to the specific authentication driver. An attacker can authenticate at one enabled social provider using a user ID matching an account linked to a different social provider, bypassing all credential verification. The vulnerable query ignores the driver column when retrieving linked social account records, allowing cross-provider account confusion attacks. The vulnerability affects BookStack before version 26.05.5 and is network-accessible without authentication or user interaction required. The fix scopes social account queries to the specific social login system (driver) to prevent mismatched account lookups.

## Affected products

- BookStack BookStack before 26.05.5

## Timeline

- 2026-09-15: disclosed
- 2026-09-14: patched: Fix released in version 26.05.5

## References

- [https://www.bookstackapp.com/blog/bookstack-release-v26-05-5/](https://www.bookstackapp.com/blog/bookstack-release-v26-05-5/)
- [https://www.vulncheck.com/advisories/bookstack-authentication-bypass-via-social-login-provider-confusion](https://www.vulncheck.com/advisories/bookstack-authentication-bypass-via-social-login-provider-confusion)