# CVE-2026-89022

## Summary

- **CVE ID:** CVE-2026-89022
- **Severity:** CRITICAL
- **CVSS Score:** 9.1 (CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N)
- **CWE:** CWE-290
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 15, 2026

## Description

BookStack before 26.05.5 contains an authentication bypass vulnerability in its social login implementation that allows unauthenticated attackers to sign in as arbitrary users by authenticating through a different social provider sharing the same driver_id namespace. Attackers can authenticate at one enabled social provider using a user ID that matches an account linked to a different social provider, bypassing credential verification entirely because the SocialAuthService::handleLoginCallback query ignores the driver column when retrieving linked account records.

## Affected Products

- bookstackapp — bookstack (0)

## References

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

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.29%
- **EPSS Percentile:** 21.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._