Post SMTP Plugin up to 4.0.1 on WordPress user_email cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Post SMTP Plugin up to 4.0.1. Affected by this vulnerability is an unknown functionality. The manipulation of the argument user_email leads to cross site scripting. This vulnerability is uniquely identified as CVE-2026-75962. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability was found in Post SMTP Plugin up to 4.0.1 and classified as problematic. This issue affects an unknown functionality. The manipulation of the argument user_email with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to 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. Impacted is integrity. The summary by CVE is:

The Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'user_email' parameter in all versions up to, and including, 4.0.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This is exploitable without authentication on WordPress Multisite installations with public registration enabled, as WordPress accepts email addresses containing numeric HTML character references that Post SMTP's stricter validator rejects, persisting the attacker-controlled address verbatim to the email log via the failed-send exception message.

The advisory is shared at wordfence.com. The identification of this vulnerability is CVE-2026-75962 since 08/18/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1059.007 for this issue.

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-2026-92961). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• WordPress Plugin

Name

• Post SMTP Plugin

Version

• 4.0.0
• 4.0.1

CPE 2.3info

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• 🔒

CPE 2.2info

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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