Newsletters Lite Plugin up to 4.15 on WordPress Shortcode helpers/shortcode.php post_thumbnail Link cross site scripting

Summaryinfo

A vulnerability identified as problematic has been detected in Newsletters Lite Plugin up to 4.15. Affected by this vulnerability is the function post_thumbnail of the file helpers/shortcode.php of the component Shortcode Handler. This manipulation of the argument Link causes cross site scripting. This vulnerability appears as CVE-2026-12939. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability has been found in Newsletters Lite Plugin up to 4.15 and classified as problematic. Affected by this vulnerability is the function post_thumbnail of the file helpers/shortcode.php of the component Shortcode Handler. The manipulation of the argument link with an unknown input leads to a cross site scripting vulnerability. The CWE definition for the vulnerability is CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. As an impact it is known to affect integrity. The summary by CVE is:

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.

It is possible to read the advisory at wordfence.com. This vulnerability is known as CVE-2026-12939 since 06/22/2026. The exploitation appears to be easy. The attack can be launched remotely. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

By approaching the search of inurl:helpers/shortcode.php it is possible to find vulnerable targets with Google Hacking.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-50096). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• WordPress Plugin

Name

• Newsletters Lite Plugin

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8
• 4.9
• 4.10
• 4.11
• 4.12
• 4.13
• 4.14
• 4.15

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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