CVE-2026-9721 | Book a Room Event Calendar <= 1.9 - Cross-Site Request Forgery to Settings Update

The Book a Room Event Calendar plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.9. This is due to missing or incorrect nonce validation on the settings_form()/update_settings() functionality. The plugin's options page handler dispatches on the 'action' POST parameter and calls update_settings(), which persists plugin configuration (including the external database host, username, password, prefix, database name, encryption key, and registration page URL) via update_option(), without ever generating a nonce field in the settings form or verifying one (no wp_nonce_field(), check_admin_referer(), or wp_verify_nonce() exists anywhere in the plugin). This makes it possible for unauthenticated attackers to modify the plugin's database connection settings via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

Published: 2026-06-24 Last update: 2026-06-24 Assigner: [email protected] Source: [email protected]
NVD Status：Received，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-9721 is rated Low Risk (17.6/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.10%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-9721

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-24 — 0.10% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-9721

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]

Weakness enumeration for CVE-2026-9721

GitHub Security Advisory for CVE-2026-9721

GHSA-pfhp-jm8f-gx6g · Severity: medium — The Book a Room Event Calendar plugin for WordPress is vulnerable to Cross-Site Request Forgery...

Affected software / configurations for CVE-2026-9721

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2026-9721

cvelogic Threat Intelligence