CVE-2021-3902Network attack vector

SSRF and file disclosure via unchecked SVG references

Published Nov 15, 2024 · Updated Nov 18, 2024

XXE in the SVG parser in dompdf before 2.0.0 allows remote attackers to perform SSRF, read internal images, or trigger PHAR deserialization. Cache::resolve_url accepts nested image href values from an SVG without recursively validating their resolved protocols and resource restrictions. An application must render attacker-controlled HTML containing an SVG image reference; isRemoteEnabled=false does not block the path, which can reach internal resources or invoke PHAR handling.

CVSS severity9.8
Critical
EPSS probability0.95%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

XXE in the SVG parser in dompdf before 2.0.0 allows remote attackers to perform SSRF, read internal images, or trigger PHAR deserialization. Cache::resolve_url accepts nested image href values from an SVG without recursively validating their resolved protocols and resource restrictions. An application must render attacker-controlled HTML containing an SVG image reference; isRemoteEnabled=false does not block the path, which can reach internal resources or invoke PHAR handling.

The record

CVE
CVE-2021-3902
Published
Nov 15, 2024
Updated
Nov 18, 2024
Vendor
dompdf
Product
dompdf
Classifications
CWE-611, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 15, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 18, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2.0.0
  2. Affected versionversion=unspecified <2.0.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

dompdf · dompdfversion=0 <2.0.0; version=unspecified <2.0.0

Published CVSS scores

9.8huntr.devCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-611Improper Restriction of XML External Entity Reference
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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