Mailgun for Plugin up to 2.2.0 on WordPress add_list addresses server-side request forgery

Summaryinfo

A vulnerability described as critical has been identified in Mailgun for Plugin up to 2.2.0. Affected is the function add_list. Executing a manipulation of the argument addresses can lead to server-side request forgery. The identification of this vulnerability is CVE-2026-78003. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability has been found in Mailgun for Plugin up to 2.2.0 and classified as critical. This vulnerability affects the function add_list. The manipulation of the argument addresses with an unknown input leads to a server-side request forgery vulnerability. The CWE definition for the vulnerability is CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The Mailgun for WordPress plugin for WordPress is vulnerable to Server-Side Request Forgery (SSRF) via path traversal in versions up to and including 2.2.0. This is due to insufficient input validation in the add_list() function, which accepts user-controlled array keys from $_POST['addresses'], passes them through sanitize_text_field(). This makes it possible for unauthenticated attackers to make authenticated POST requests to any Mailgun API endpoint using the WordPress site's API key, including creating inbound email-forwarding routes that can intercept password reset emails, leading to administrator account takeover.

The advisory is available at wordfence.com. This vulnerability was named CVE-2026-78003 since 08/21/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/22/2026).

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

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Productinfo

Type

• WordPress Plugin

Name

• Mailgun for Plugin

Version

• 2.0
• 2.1
• 2.2.0

CPE 2.3info

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CPE 2.2info

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