by Kastro
Paper/Archive/CVE-2026-89022

CVE-2026-89022

bookstackapp bookstack — BookStack < 26.05.5 Authentication Bypass via Social Login Provider Confusion

EPSS 0.5%CVSS 9.1
critical.is priorityof 100
35
CVSS 9.1 (CNA)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 40.2.402 × 208.0No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
bookstack< 26.05.526.05.5CNA

Scores by source

VulnCheck (CNA)9.1CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
VulnCheck (CNA)7.4CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

advisorybookstackapp.com/blog/bookstack-release-v26-05-5writeupvulncheck.com/advisories/bookstack-authentication-bypass-via-social-login-provider-confusion