What’s Vulnerable › Vulnerabilities

CVE-2021-34551

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-16 · updated 2026-06-17
• Weakness: CWE-434

Description

PHPMailer before 6.5.0 on Windows allows remote code execution if lang_path is untrusted data and has a UNC pathname.

Affected products

• Fedoraproject Fedora: 33, 34
• Phpmailer Project Phpmailer: before 6.5.0 — fixed in 6.5.0

How to fix

Upgrade to a fixed version: Phpmailer Project Phpmailer 6.5.0. Check the vendor advisory for mitigations.

References

• https://github.com/PHPMailer/PHPMailer/blob/master/SECURITY.md
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3YRMWGA4VTMXFB22KICMB7YMFZNFV3EJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FJYSOFCUBS67J3TKR74SD3C454N7VTYM/
• https://github.com/PHPMailer/PHPMailer/blob/master/SECURITY.md
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3YRMWGA4VTMXFB22KICMB7YMFZNFV3EJ/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FJYSOFCUBS67J3TKR74SD3C454N7VTYM/

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