CVE-2026-78003 mailgun CVE debrief

Who should care

WordPress administrators and users of the Mailgun for WordPress plugin should assess exposure and prioritize patching, reviewing compensating controls for exposed systems while remediation is scheduled and verified, and monitor for suspicious activity on Mailgun API endpoints.

Why it matters

The Mailgun for WordPress plugin vulnerability allows unauthenticated attackers to make authenticated POST requests to any Mailgun API endpoint, potentially leading to administrator account takeover and interception of password reset emails. WordPress administrators and users of the Mailgun for WordPress plugin should assess exposure and prioritize patching.

• Potential for administrator account takeover
• Possible interception of password reset emails
• Unauthenticated access to Mailgun API endpoints
• Potential for lateral movement within the network

Technical summary

The Mailgun for WordPress plugin is vulnerable to Server-Side Request Forgery (SSRF) via path traversal in versions up to and including 2.2.0. An unauthenticated attacker can make authenticated POST requests to any Mailgun API endpoint using the WordPress site's API key, allowing potential for administrator account takeover and interception of password reset emails. 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().

Defensive priority

High priority for patching and verifying affected versions

Recommended defensive actions

• Patch the Mailgun for WordPress plugin to version greater than 2.2.0
• Verify affected versions and update to a patched version
• Monitor for suspicious activity on Mailgun API endpoints
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Review compensating controls for exposed systems while remediation is scheduled and verified.

Evidence notes

The vulnerability was reported by [email protected] and is described in the CVE Program record and NVD vulnerability detail pages. The Mailgun for WordPress plugin 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().

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.