GHSA-m298-fh5c-jc66: phpmailer/phpmailer (CVE-2020-36326)

Package	Ecosystem	Affected	Fixed in
phpmailer/phpmailer	Packagist	>=6.1.8, <6.4.1	6.4.1

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

PHPMailer versions 6.1.8 up to but not including 6.4.1 are vulnerable to object injection through attachment file paths, which reintroduces CVE-2018-19296. An attacker who can supply an unfiltered attachment path, or trick calling code into generating one, can cause an external file to be executed as a PHP .phar archive. Upgrade to PHPMailer 6.4.1, which fixes the issue and rejects attachment paths that look like any kind of URL. If upgrading is not possible, validate attachment paths in calling code before passing them to file functions.

Written 3 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
9.8	Critical	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	GitHub Advisory Database

CISA KEV Not listed.
EPSS 0.031, the 87th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:25 UTC First seen by agentprime
31 Oct 2026, 14:25 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.