CVE-2023-24813 URI validation failure on SVG parsing. Bypass of CVE-2023-23924

2023-02-0718:05:14

CWE-436

GitHub_M

www.cve.org

svg parsing

dompdf

uri validation

arbitrary urls

php

vulnerability

commit 95009ea98

upgrade

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

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

AI Score

9.8

Confidence

High

EPSS

0.011

Percentile

84.6%

JSON

Dompdf is an HTML to PDF converter written in php. Due to the difference in the attribute parser of Dompdf and php-svg-lib, an attacker can still call arbitrary URLs with arbitrary protocols. Dompdf parses the href attribute of image tags and respects xlink:href even if href is specified. However, php-svg-lib, which is later used to parse the svg file, parses the href attribute. Since href is respected if both xlink:href and href is specified, it’s possible to bypass the protection on the Dompdf side by providing an empty xlink:href attribute. An attacker can exploit the vulnerability to call arbitrary URLs with arbitrary protocols if they provide an SVG file to the Dompdf. In PHP versions before 8.0.0, it leads to arbitrary unserialize, which will lead, at the very least, to arbitrary file deletion and might lead to remote code execution, depending on available classes. This vulnerability has been addressed in commit 95009ea98 which has been included in release version 2.0.3. Users are advised to upgrade. There are no known workarounds for this vulnerability.

CNA Affected

[
  {
    "vendor": "dompdf",
    "product": "dompdf",
    "versions": [
      {
        "version": "= 2.0.2",
        "status": "affected"
      }
    ]
  }
]