A high-severity vulnerability in the All-in-One WP Migration and Backup WordPress plugin exposes over 3 million websites to remote code execution (RCE) attacks, WordPress security firm Defiant warns.
Tracked as CVE-2026-19949 (CVSS score of 8.8), the security defect is described as a second-order SQL injection issue in the archive restore functionality of the plugin.
The flaw exists because user-supplied input is insufficiently escaped and existing SQL queries are not sufficiently prepared, Defiant explains.
An attacker could supply malicious content via WordPress core’s trackback functionality to extract the secret key used during an archive restore operation, and then use the key to deploy a malicious plugin for RCE.
All-in-One WP Migration and Backup packages sites into .wpress archives and allows admins to restore the archive on any destination server. The import operation is unauthenticated, but protected using a secret key that is saved during each database-restore pass.
CVE-2026-19949 allows an attacker to submit two trackbacks to a public post, each carrying a trailing backslash and a URL leading to a payload. The input is saved without backslashes being stripped or the URLs being rejected.
Once an administrator archives and then imports the site, the plugin rewrites URLs and table prefixes in the stored SQL; the attacker-supplied input is promoted to executable SQL, which results in the secret key value being written to a comment that is approved and becomes publicly visible.
An unauthenticated attacker could then retrieve the secret key from the site’s comments REST API endpoint and use it to import a crafted .wpress archive containing a malicious must-use plugin that is executed upon the next page load, leading to RCE.
“As with all remote code execution vulnerabilities, this can lead to complete site compromise through the use of webshells and other techniques,” Defiant notes.
The vulnerability impacts all All-in-One WP Migration and Backup versions up to 7.109 and was patched in version 7.110, which was released on August 20.
A highly popular backup and restore WordPress tool, the plugin has over 5 million active deployments. As of September 3, only 35% of all installations have been updated to version 7.110, meaning that roughly 3.2 million sites are running a vulnerable plugin iteration, WordPress data shows.
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