Wordpress Core < 5.5 — Unauthorized Password Reset via Interception

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under WordPress.
• No admin access? Run a passive check of your site. It reads public files only.
• No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

1. Update to version 5.5, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch WordPress to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Dawid Golunski.

WordPress up to version 5.5 relies on the Host HTTP header for a password-reset e-mail message, which makes it easier for remote attackers to reset arbitrary passwords by making a crafted wp-login.php?action=lostpassword request and then arranging for this message to bounce or be resent, leading to transmission of the reset key to a mailbox on an attacker-controlled SMTP server. This is related to problematic use of the SERVER_NAME variable in wp-includes/pluggable.php in conjunction with the PHP mail function. Exploitation is not achievable in all cases because it requires at least one of the following: (1) the attacker can prevent the victim from receiving any e-mail messages for an extended period of time (such as 5 days), (2) the victim's e-mail system sends an autoresponse containing the original message, or (3) the victim manually composes a reply containing the original message.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Timeline

1. May 3, 2017

   CVE published

   Severity medium, CVSS 5.9

2. Nov 13, 2026

   Record last updated