CVE-2026-78003 Mailgun for WordPress <= 2.2.0 - Unauthenticated Server-Side Request Forgery (SSRF) via 'addresses' Array Keys
Unauthenticated attackers can exploit SSRF to intercept password reset emails and take over administrator accounts via the Mailgun plugin.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-78003?
CVE-2026-78003 is a critical server-side request forgery vulnerability in Mailgun for WordPress, published on 22 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-918
Which versions are affected by CVE-2026-78003?
How do I fix CVE-2026-78003?
No fix has been published for CVE-2026-78003 yet. Limit exposure of the affected software until one is available.
Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.
Is CVE-2026-78003 being exploited?
There is no known exploitation of CVE-2026-78003 in the wild and no public exploit code.
Sources
Also known as GHSA-jr9c-873v-948h.