---
id: CVE-2026-89022
title: >-
  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…
summary: >-
  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…
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'
cwe:
  - CWE-290
vendor: bookstackapp
product: bookstack
affected:
  - bookstack < 26.05.5
published: '2026-09-15'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T19:47:01.197'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89022'
references:
  - url: 'https://www.bookstackapp.com/blog/bookstack-release-v26-05-5/'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/bookstack-authentication-bypass-via-social-login-provider-confusion
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-15T19:04:04.179125Z'
ingestedAt: '2026-09-15T16:40:03.398Z'
epss: 0.00465
epssPercentile: 0.3764
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.