XSS in Advplyr Audiobookshelf

CVE-2026-42887

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.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (28.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 28th percentile — 28.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-42887: held from 0.002 to 0.004.

EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-42887?
CVE-2026-42887 is a medium-severity vulnerability in Advplyr Audiobookshelf, classified under Cross-site Scripting. CVSS score: 4.5/10. Published 2026-05-11.
How severe is CVE-2026-42887?
Medium severity. CVSS v3 base score is 4.5 out of 10.