What the vulnerability does
01Description
The Newsletters Lite plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'link' attribute of the post_thumbnail (and newsletters_post_thumbnail) shortcodes in versions up to and including 4.15. This is due to insufficient input sanitization and output escaping in the post_thumbnail() method in helpers/shortcode.php, which concatenates the user-controlled $link shortcode attribute directly into an href attribute without esc_url() or esc_attr(). This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
Explanation of Vulnerability in Simple Terms
02Summary
Contrid Newsletters versions 4.15 and earlier contain a cross-site scripting (XSS) vulnerability that allows authenticated users to inject malicious scripts affecting other users. The vulnerability has scope change, meaning injected code can impact areas beyond the vulnerable component. Low-privileged accounts can exploit this without user interaction.
What an attacker can do
03Attacker Capabilities
Inject malicious scripts that execute in other users' browsers and affect site functionality.
Potential impact on your site
04Site Impact
Authenticated users can inject code affecting other visitors; potential for credential theft, malware distribution, or site defacement.
Conditions required to exploit
05Prerequisites
Attacker must have a low-privileged account on the site; no user interaction required.
Key dates
06Disclosure timeline
July 29, 2026
CVE published
July 29, 2026
Record updated
