#VU52850 Deserialization of Untrusted Data in PHPMailer - CVE-2020-36326

Vulnerability identifier: #VU52850

Vulnerability risk: High

CVSSv4.0: 6.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2020-36326

CWE-ID: CWE-502

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PHPMailer
Web applications / Other software

Vendor: phpmailer.sourceforge.net

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to insecure input validation when processing serialized data in "addAttachment". A remote attacker can pass specially crafted data to the application and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

PHPMailer: 6.1.8 - 6.4.0

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External links
https://github.com/PHPMailer/PHPMailer/commit/e2e07a355ee8ff36aba21d0242c5950c56e4c6f9
https://github.com/PHPMailer/PHPMailer/commit/26f2848d3bbb57add5f34a467a1e3b2f9ce5cd2a

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.