CVE-2021-3838: PHAR Deserialization in dompdf/dompdf

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2024-11-15 · updated 2026-06-17
Weakness: CWE-502

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.

Affected products

dompdf: before 2.0.0 — fixed in 2.0.0
Packagist Dompdf/Dompdf: before 2.0.0; v0.6.0, v0.6.1, v0.6.2, v0.7.0, v0.7.0-beta, v0.7.0-beta2 (+16) — fixed in 2.0.0

How to fix

Upgrade to a fixed version: dompdf 2.0.0; Packagist Dompdf/Dompdf 2.0.0. Check the vendor advisory for mitigations.

References

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