CVE-2021-3902

Dompdf insecure deserialization

9.8 CRITICALEPSS 0.95%

Published15 Nov 2024

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Affected products

Dompdf< 2.0.0

Remediation

Fixed in

Dompdf≥ 2.0.0

Frequently asked

Is CVE-2021-3902 being actively exploited?

CVE-2021-3902 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.95%.

How severe is CVE-2021-3902?

CVE-2021-3902 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.95% probability of exploitation.

Which products are affected by CVE-2021-3902?

Affected products include Dompdf.

How do I fix CVE-2021-3902?

Upgrade affected software to a fixed version, for example Dompdf 2.0.0 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-3902 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.