WP Books Gallery <= 4.8.0 - Missing Authorization to Unauthenticated Settings Update via 'permalink_structure' Parameter
Strategic Overview
- Status
- Patched in 4.8.1
- Affected Plugin
- Books Gallery – Book Showcase, Library & Affiliate Plugin
- Affected Version
<= 4.8.0- CVSS
- 5.3Medium
- Weakness type
- CWE-862 · Missing Authorization
- CVE
CVE-2026-5347
At a glance
CVE-2026-5347 is a medium-severity Missing Authorization vulnerability in the Books Gallery WordPress plugin, affecting versions <= 4.8.0. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 4.8.1; sites on affected versions should update now. Disclosed April 2026, reported by Legion Hunter.
Vulnerability Overview
The HM Books Gallery plugin for WordPress is vulnerable to Missing Authorization in versions up to and including 4.8.0. This is due to the absence of capability checks and nonce verification in the admin_init hook that handles the permalink settings update at line 205-209 of wp-books-gallery.php. The vulnerable code checks only for the presence of the 'permalink_structure' POST parameter before updating the 'wbg_cpt_slug' option, without verifying that the request comes from an authenticated administrator. This makes it possible for unauthenticated attackers to modify the custom post type slug for the books gallery, which changes the URL structure for all book entries and can break existing links and SEO rankings.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.
CWE-862: Missing Authorization
Books Gallery <= 4.8.0 carries this weakness at permalink_structure, and reaching it takes no account at all. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.
Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Books Gallery the fix is 4.8.1: builds <= 4.8.0 are affected, anything from 4.8.1 onward is not.
Remediation
Update to version 4.8.1, or a newer patched version
How does WordSec protect against this?
This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Books Gallery 4.8.1 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Same weakness class
Other vulnerabilities in Books Gallery – Book Showcase, Library & Affiliate Plugin
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