High severity8.1NVD Advisory· Published Jun 17, 2021· Updated Jun 17, 2026
CVE-2021-3603
CVE-2021-3603
Description
PHPMailer 6.4.1 and earlier contain a vulnerability that can result in untrusted code being called (if such code is injected into the host project's scope by other means). If the $patternselect parameter to validateAddress() is set to 'php' (the default, defined by PHPMailer::$validator), and the global namespace contains a function called php, it will be called in preference to the built-in validator of the same name. Mitigated in PHPMailer 6.5.0 by denying the use of simple strings as validator function names.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
phpmailer/phpmailerPackagist | < 6.5.0 | 6.5.0 |
Affected products
6cpe:2.3:a:phpmailer_project:phpmailer:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:phpmailer_project:phpmailer:*:*:*:*:*:*:*:*range: <=6.4.1
- (no CPE)range: unspecified
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
- osv-coords2 versions
< 6.4.2+ 1 more
- (no CPE)range: < 6.4.2
- (no CPE)range: < 6.5.0
Patches
Vulnerability mechanics
References
13- github.com/PHPMailer/PHPMailer/commit/45f3c18dc6a2de1cb1bf49b9b249a9ee36a5f7f3nvdPatchThird Party AdvisoryWEB
- github.com/advisories/GHSA-77mr-wc79-m8j3ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2021-3603ghsaADVISORY
- github.com/FriendsOfPHP/security-advisories/blob/master/phpmailer/phpmailer/CVE-2021-3603.yamlghsaWEB
- github.com/PHPMailer/PHPMailer/releases/tag/v6.5.0ghsaWEB
- github.com/PHPMailer/PHPMailer/security/advisories/GHSA-77mr-wc79-m8j3ghsaWEB
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3YRMWGA4VTMXFB22KICMB7YMFZNFV3EJghsaWEB
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FJYSOFCUBS67J3TKR74SD3C454N7VTYMghsaWEB
- web.nvd.nist.gov/view/vuln/detailghsaWEB
- www.huntr.dev/bounties/1-PHPMailer/PHPMailerghsaWEB
- www.huntr.dev/bounties/1-PHPMailer/PHPMailer/nvdProduct
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3YRMWGA4VTMXFB22KICMB7YMFZNFV3EJ/nvd
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FJYSOFCUBS67J3TKR74SD3C454N7VTYM/nvd
News mentions
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