CVE-2021-3902

Name: CVE-2021-3902
Creator: NVD / NIST
Published: 2024-11-15T11:15:06.19+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 0.92%

Last modified Jun 17, 2026

CVE-2021-3902 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. An improper restriction of external entities (XXE) vulnerability in dompdf/dompdf's SVG parser allows for Server-Side Request Forgery (SSRF) and deserialization attacks. This issue affects all versions prior to 2.0.0. EPSS estimates a 0.92% chance of exploitation in the next 30 days.

Description

An improper restriction of external entities (XXE) vulnerability in dompdf/dompdf's SVG parser allows for Server-Side Request Forgery (SSRF) and deserialization attacks. This issue affects all versions prior to 2.0.0. The vulnerability can be exploited even if the isRemoteEnabled option is set to false. It allows attackers to perform SSRF, disclose internal image files, and cause PHAR deserialization attacks.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

0.92%

55.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-611

Affected Software

Vendor	Product	Versions
Dompdf Project	Dompdf	< 2.0.0

References

https://github.com/dompdf/dompdf/commit/f56bc8e40be6c0ae0825e6c7396f4db80620b799Patch
https://huntr.com/bounties/a6071c07-806f-429a-8656-a4742e4191b1Exploit, Issue Tracking, Patch, Third Party Advisory

Timeline

Published: Nov 15, 2024
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-3902?

How severe is CVE-2021-3902?

CVE-2021-3902 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.92% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3902?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3902?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST