CVE-2026-47423
Description
A flaw was found in DOMPurify, a DOM-only cross-site scripting (XSS) sanitizer. Due to the default allowance of selectedcontent, a remote attacker could craft a malicious payload that, after initial sanitization, could be re-cloned by browsers, leading to the execution of unsanitized markup. This could result in information disclosure.
Statement
This is a cross-site scripting (XSS) vulnerability in DOMPurify, a sanitizer for HTML, MathML, and SVG. The flaw allows a remote attacker to bypass sanitization by crafting a malicious payload that leverages the default allowance of selectedcontent. This can lead to browsers re-cloning the payload and executing unsanitized markup, resulting in information disclosure. User interaction is required for exploitation.
- AC was raised from Low to High because exploitation requires specific browser support for the experimental
HTML element, which is currently only available in Chromium 148+ and WebKit 625+. Firefox and Safari are not affected, and only the single DOMPurify version 3.4.4 is vulnerable (fixed in 3.4.5), significantly narrowing the attack surface. - Scope was lowered from Changed to Unchanged because the XSS executes within the same origin as the consuming application with no cross-domain scope change.
No Red Hat product ships dompurify 3.4.4.
Mitigation
There is no direct mitigation for this flaw other than updating the DOMPurify library when upstream patches are available. As a defense-in-depth measure, Content Security Policy (CSP) headers that restrict inline script execution can help reduce the impact of XSS vulnerabilities.
This issue is fixed in version 3.4.5.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | 8.2 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Changed |
| Confidentiality | High | N/A | High |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
Red Hat CVSS v3 Score Explanation
AC:L raised to AC:H — only DOMPurify 3.4.4 (single version) is affected, and exploitation requires Chromium 148+ or WebKit 625+ with experimental
Understanding the Weakness (CWE)
Access Control,Confidentiality
Technical Impact: Bypass Protection Mechanism; Read Application Data
The most common attack performed with cross-site scripting involves the disclosure of private information stored in user cookies, such as session information. Typically, a malicious user will craft a client-side script, which -- when parsed by a web browser -- performs some activity on behalf of the victim to an attacker-controlled system (such as sending all site cookies to a given E-mail address). This could be especially dangerous to the site if the victim has administrator privileges to manage that site. This script will be loaded and run by each user visiting the web site. Since the site requesting to run the script has access to the cookies in question, the malicious script does also.
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
In some circumstances it may be possible to run arbitrary code on a victim's computer when cross-site scripting is combined with other flaws, for example, "drive-by hacking."
Confidentiality,Integrity,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Read Application Data
The consequence of an XSS attack is the same regardless of whether it is stored or reflected. The difference is in how the payload arrives at the server. XSS can cause a variety of problems for the end user that range in severity from an annoyance to complete account compromise. Some cross-site scripting vulnerabilities can be exploited to manipulate or steal cookies, create requests that can be mistaken for those of a valid user, compromise confidential information, or execute malicious code on the end user systems for a variety of nefarious purposes. Other damaging attacks include the disclosure of end user files, installation of Trojan horse programs, redirecting the user to some other page or site, running "Active X" controls (under Microsoft Internet Explorer) from sites that a user perceives as trustworthy, and modifying presentation of content.
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