5.3

CVSS Score

3.1

-

CVSS Score

Basic Information

CVE ID

CVE-2023-50262

GHSA ID

GHSA-3qx2-6f78-w2j2

EPSS Score

0.88979%

CWE

CWE-20

Published

12/13/2023

Updated

12/18/2023

KEV Status

Technology

PHP

Basic Information

CVE ID

GHSA ID

EPSS Score

CWE

Published

Updated

KEV Status

Technology

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CVE-2023-50262

CVE-2023-50262: Denial of service caused by infinite recursion when parsing SVG images

Summary

When parsing SVG images Dompdf performs an initial validation to ensure that paths within the SVG are allowed. One of the validations is that the SVG document does not reference itself. However, a recursive chained using two or more SVG documents is not correctly validated. Depending on the system configuration and attack pattern this could exhaust the memory available to the executing process and/or to the server itself.

Details

php-svg-lib, when run in isolation, does not support SVG references for image elements. An SVG document can, however, be referenced and Dompdf will run that reference through the same validation. Dompdf currently includes validation to prevent self-referential image references, but a chained reference is not checked. A malicious actor may thus trigger infinite recursion in the validation process by chaining references between two or more SVG images.

PoC

This following sources can be used to bypass validation provided by Dompdf:

recurse.html

<img src="one.svg">

one.svg

<svg width="200" height="200" xmlns="http://www.w3.org/2000/svg">
  <image href="two.svg" />
</svg>

two.svg

<svg width="200" height="200" xmlns="http://www.w3.org/2000/svg">
  <image href="one.svg" />
</svg>

Impact

When Dompdf parses the above payload, it will crash due after exceeding the allowed execution time or memory usage. An attacker sending multiple request to a system can potentially cause resource exhaustion to the point that the system is unable to handle incoming request.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2023-50262

CVE-2023-50262:

5.3

CVSS Score

3.1

-

CVSS Score

Basic Information

CVE ID

CVE-2023-50262

GHSA ID

GHSA-3qx2-6f78-w2j2

EPSS Score

0.88979%

CWE

CWE-20

Published

12/13/2023

Updated

12/18/2023

KEV Status

Technology

PHP

Basic Information

CVE ID

GHSA ID

EPSS Score

CWE

Published

Updated

KEV Status

Technology

Technical Details

CVSS Vector

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

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
dompdf/dompdf	composer	< 2.0.4	2.0.4

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The vulnerability stems from how resolve_url() handles SVG image references. The pre-patch code in lines 136-153 of Cache.php only checked if an SVG directly references itself (inner_full_url === full_url), but didn't maintain state across document validations. This allowed chained references between multiple SVGs to bypass validation. The commit added a $svgRefs tracking array and detectCircularRef() method to address this, confirming the vulnerability existed in the original resolve_url implementation's reference validation logic.

Vulnerable functions

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WAF Protection Rules

WAF Rule

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Reasoning

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5.3

-

Basic Information

Basic Information

Concerned about an active attack path?

CVE-2023-50262: Denial of service caused by infinite recursion when parsing SVG images

Summary

Details

PoC

Impact

CVE-2023-50262:

5.3

-

Basic Information

Basic Information

Technical Details

Technical Details

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

Vulnerability IntelligenceMiggo AI

Basic Information

Basic Information

Technical Details

CVE-2023-50262: Denial of service caused by infinite recursion when parsing SVG images

Summary

Details

PoC

Impact

Vulnerability IntelligenceMiggo AI

Root Cause Analysis

Vulnerable functions

WAF Protection Rules

WAF Rule

Reasoning

5.3

5.3

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI

Vulnerability Intelligence
Miggo AI