CVE-2026-42887: Audiobookshelf: Stored Cross-Site Scripting in Login Page Custom Message

Severity: medium (CVSS 4.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-11 · updated 2026-10-26
Weakness: CWE-79

Description

Audiobookshelf is a self-hosted audiobook and podcast server. Prior to 2.33.0, a stored cross-site scripting (XSS) vulnerability exists in the Login Page due to improper sanitization of the authLoginCustomMessage field of the /api/auth-settings endpoint. An attacker with administrative privileges can inject arbitrary HTML/JavaScript that will be rendered on the login page for all users. This vulnerability is fixed in 2.33.0.

Affected products

advplyr audiobookshelf: before 2.33.0

References

https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-cx29-ghq2-9cm4
https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-cx29-ghq2-9cm4

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