Is CVE-2021-3838 actively exploited?

No active exploitation of CVE-2021-3838 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-3838 be exploited remotely?

Yes. CVE-2021-3838 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-3838?

CVE-2021-3838 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-3838

CWE-502Published: November 15, 2024· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

DomPDF before version 2.0.0 is vulnerable to PHAR deserialization due to a lack of checking on the protocol before passing it into the file_get_contents() function. An attacker who can upload files of any type to the server can pass in the phar:// protocol to unserialize the uploaded file and instantiate arbitrary PHP objects. This can lead to remote code execution, especially when DOMPdf is used with frameworks with documented POP chains like Laravel or vulnerable developer code.

NVD Source

Technical Analysis

CVE-2021-3838 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

From a weakness classification perspective (CWE-502): Insecure deserialization vulnerabilities allow attackers to inject malicious objects during deserialization, potentially enabling remote code execution.