Cyber Resilience

CVE-2021-3902

CriticalPublic PoC

Published: 15 November 2024

Published
15 November 2024
Modified
19 November 2024
KEV Added
—
Patch
—
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0509 90.0th percentile
Risk Priority 23 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-3902 is a critical-severity Improper Restriction of XML External Entity Reference (CWE-611) vulnerability in Dompdf Project Dompdf. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 10.0% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

set to false. It allows attackers to perform SSRF, disclose internal image files, and cause PHAR deserialization attacks.

CWE(s)
CWE-611

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

dompdf project
dompdf
≤ 2.0.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-611

Penetration testing includes XML external entity payloads, detecting XXE vulnerabilities and enabling their mitigation.

SI-4 System Monitoring
addresses: CWE-611

Identifies XML external entity processing via monitoring of unusual file/network access or resource usage.

References