CVE-2021-3603

Inclusion of Functionality from Untrusted Control Sphere in PHPMailer/PHPMailer

HIGH
8.1
CVSS Score
Published: June 17, 2021 at 12:09 PM UTC
Updated: June 17, 2026 at 04:05 AM UTC
3 products affected across 3 vendorsFedoraPhpmailerPHPMailer

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Severity
HIGH8.1
Exploit prediction
EPSS 2%

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v ≤ 6.4.1
v < 6.5.0
Affected range stops below 6.5.0, so it looks safe — our inference, not a vendor statement

CVSS

8.1HIGH@huntrdev
Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-829

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