CVE-2021-36845
CWE-79Published: September 27, 2021· Updated: Jun 17, 2026
Official Description
Multiple Authenticated Stored Cross-Site Scripting (XSS) vulnerabilities in YITH Maintenance Mode (WordPress plugin) versions <= 1.3.8, there are 46 vulnerable parameters that were missed by the vendor while patching the 1.3.7 version to 1.3.8. Vulnerable parameters: 1 - "Newsletter" tab, &yith_maintenance_newsletter_submit_label parameter: payload should start with a single quote (') symbol to break the context, i.e.: NOTIFY ME' autofocus onfocus=alert(/Visse/);// v=' - this payload will be auto triggered while admin visits this page/tab. 2 - "General" tab issues, vulnerable parameters: &yith_maintenance_message, &yith_maintenance_custom_style, &yith_maintenance_mascotte, &yith_maintenance_title_font[size], &yith_maintenance_title_font[family], &yith_maintenance_title_font[color], &yith_maintenance_paragraph_font[size], &yith_maintenance_paragraph_font[family], &yith_maintenance_paragraph_font[color], &yith_maintenance_border_top. 3 - "Background" tab issues, vulnerable parameters: &yith_maintenance_background_image, &yith_maintenance_background_color. 4 - "Logo" tab issues, vulnerable parameters: &yith_maintenance_logo_image, &yith_maintenance_logo_tagline, &yith_maintenance_logo_tagline_font[size], &yith_maintenance_logo_tagline_font[family], &yith_maintenance_logo_tagline_font[color]. 5 - "Newsletter" tab issues, vulnerable parameters: &yith_maintenance_newsletter_email_font[size], &yith_maintenance_newsletter_email_font[family], &yith_maintenance_newsletter_email_font[color], &yith_maintenance_newsletter_submit_font[size], &yith_maintenance_newsletter_submit_font[family], &yith_maintenance_newsletter_submit_font[color], &yith_maintenance_newsletter_submit_background, &yith_maintenance_newsletter_submit_background_hover, &yith_maintenance_newsletter_title, &yith_maintenance_newsletter_action, &yith_maintenance_newsletter_email_label, &yith_maintenance_newsletter_email_name, &yith_maintenance_newsletter_submit_label, &yith_maintenance_newsletter_hidden_fields. 6 - "Socials" tab issues, vulnerable parameters: &yith_maintenance_socials_facebook, &yith_maintenance_socials_twitter, &yith_maintenance_socials_gplus, &yith_maintenance_socials_youtube, &yith_maintenance_socials_rss, &yith_maintenance_socials_skype, &yith_maintenance_socials_email, &yith_maintenance_socials_behance, &yith_maintenance_socials_dribble, &yith_maintenance_socials_flickr, &yith_maintenance_socials_instagram, &yith_maintenance_socials_pinterest, &yith_maintenance_socials_tumblr, &yith_maintenance_socials_linkedin.
Technical Analysis
CVE-2021-36845 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
Exploitation requires high privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
The vulnerability has a "Changed" scope, meaning successful exploitation can impact components beyond the vulnerable component itself — such as the host operating system or adjacent services.
From a weakness classification perspective (CWE-79): Cross-site scripting (XSS) vulnerabilities allow attackers to inject malicious scripts into web pages viewed by other users.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
Official Patches & Advisories
All References (4)
Quick Facts
Related CVEs (CWE-79)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-36845 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts