Vulnerability · Published Sep 15, 2026 · Assigned by VulnCheck

CVE-2026-89022BookStack < 26.05.5 Authentication Bypass via Social Login Provider Confusion

High 7.4

In plain English

A high-severity authentication bypass by spoofing in bookstack from bookstackapp. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities).

Severity (CVSS 3.1)7.4High

Exploit odds (30 days)0.5%top 59.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
bookstackapp	bookstack	0 – before 26.05.5

Weakness: CWE-290 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Vendor Advisory vendor-advisory
https://www.vulncheck.com/advisories/bookstack-authentication-bypass-via-social-login-provider-confusion third-party-advisory