CVE intelligence and bounded remediation

CVE-2021-3603 — Phpmailer Project Phpmailer security vulnerability

High CVSS 8.1

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.

Severity
High
CVSS
8.1 (3.1)
Published
2021-06-17
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-829

Affected products

  • phpmailer_project / phpmailer
  • fedoraproject / fedora / 33
  • fedoraproject / fedora / 34

Matched remediation archetype

Supply-chain, dependency, build, and update integrity

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace affected packages, source archives, build actions, plugins, installers, and updates from declared source to deployed artifact.
  • Confirm provenance, signatures or digests, namespace ownership, lockfile resolution, registry configuration, and build-runner trust boundaries.
  • Inventory direct, transitive, vendored, generated, and bundled copies across releases and distribution channels.

Remediate safely

  • Move to a maintained trusted artifact or remove the dependency; pin immutable identities and verify provenance and integrity before use.
  • Regenerate lockfiles and artifacts in a clean isolated build, minimize build credentials and network access, and produce an updated software bill of materials.
  • Require reviewed update policy, protected publishing, and reproducible or independently attestable builds where supported.

Authoritative sources

Complete CVE record and remediation plan

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