Vulnerability in Bookstackapp Bookstack
CVE-2026-89022
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.4 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.005 (40.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 40.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
Weakness classification (CWE)
References
- Vendor Advisory (vendor-advisory)
- www.vulncheck.com/advisories/bookstack-authentication-bypass-via-social-login-p… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-89022?
- CVE-2026-89022 is a high-severity vulnerability in Bookstackapp Bookstack, classified under Authentication Bypass by Spoofing. CVSS score: 7.4/10. Published 2026-09-15.
- How severe is CVE-2026-89022?
- High severity. CVSS v3 base score is 7.4 out of 10.