CVE-2026-89022

critical · 9.1

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.

9.1

CVSS

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EPSS (exploit prob.)

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EPSS percentile

2026-09-15

Published

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Weaknesses

CWE-290

References

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

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-89022