PHPMailer Command Injection Vulnerability (CVE-2016-10033)
Severity: critical · Patch status: patched · Since 2025-07-07 · CVE-2016-10033
PHPMailer contains a command injection vulnerability because it fails to sanitize user-supplied input. Specifically, this issue affects the 'mail()' function of 'class.phpmailer.php' script. An attacker can exploit this issue to execute arbitrary code within the context of the application. Failed exploit attempts will result in a denial-of-service condition. CISA added CVE-2016-10033 to its Known Exploited Vulnerabilities catalog on Jul 7, 2025, which means attackers are exploiting it in the wild.
What to do
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- US federal agencies must remediate by Jul 28, 2025 (BOD 22-01); treat that as the outer limit.
Sources
All live incidents on Threat Watch
