Object injection in PHPMailer/PHPMailer

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.8 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2020-36326: 3.09% estimated exploitation activity in the next 30 days; percentile 87.75 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact This is a reintroduction of an earlier issue (CVE-2018-19296) by an unrelated bug fix in PHPMailer 6.1.8. An external file may be unexpectedly executable if it is used as a path to an attachment file via PHP's support for .phar files. Exploitation requires that an attacker is able to provide an unfiltered path to a file to attach, or to trick calling code into generating one. See this article for more info. Patches This issue was patched in the PHPMailer 6.4.1 release. This release also implements stricter filtering for attachment paths; paths that look like any kind of URL are rejected. Workarounds Validate paths to loaded files using the same pattern as used in isPermittedPath() before using them in any PHP file function, such as fileexists. This method can't be used directly because it is protected, but you can implement the same thing in calling code. Note that this should be applied to all user-supplied paths passed into such functions; it's not a problem specific to…

Published by the source

4 May 2021, 17:42 UTC

Last modified by the source

21 Jul 2026, 13:42 UTC

Source last checked

26 Oct 2026, 14:50 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-m298-fh5c-jc66

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2020-36326

Advisory: Object injection in PHPMailer/PHPMailer
IDs: CVE-2020-36326, GHSA-m298-fh5c-jc66
Record: https://patchnext.com/advisories/cve-2020-36326 (revision 1, source checked 26 Oct 2026, 14:50 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: phpmailer/phpmailer 6.4.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist phpmailer/phpmailer: affected >= 6.1.8, < 6.4.1; fixed in 6.4.1

## Suggested inspection (read-only)
- Packagist phpmailer/phpmailer: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on phpmailer/phpmailer.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-m298-fh5c-jc66 (GitHub-reviewed advisory GHSA-m298-fh5c-jc66 lists affected ranges: Packagist phpmailer/phpmailer >=6.1.8 <6.4.1)

Commands are suggestions: review each one before running it.