CVE-2026-116802— DOMPurify before 3.4.17 XSS via SMIL attributeName Guard Bypass in XHTML Mode

Quick assessment

Affected

cure53 DOMPurify

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 3.4.17 版本之前的 DOMPurify 存在跨站脚本（XSS）漏洞。当设置为时，攻击者可绕过针对 SMIL 中的防护机制，原因是未将属性名转换为小写。攻击者可提交包含或元素的 SVG，其中设置，并在中嵌入协议链接；当用户点击经过净化的链接时，即可触发脚本执行。

CVSS 6.1 · Medium Updated Oct 27, 2026

Possible ATT&CK Techniques 2 AI

T1059.007 · JavaScript T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

DOMPurify before 3.4.17 XSS via SMIL attributeName Guard Bypass in XHTML Mode

Source: CVE Program / CVE List V5

Vulnerability Description

DOMPurify before 3.4.17 contains a cross-site scripting vulnerability that allows attackers to bypass the SMIL attributeName=href guard when PARSER_MEDIA_TYPE is application/xhtml+xml, because transformCaseFunc does not lowercase attribute names. Attackers can submit SVG with an animate or set element using attributeName="href" and a javascript: entry in values to execute script when users click the sanitized link.

Source: CVE Program / CVE List V5

CVSS Information

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

Source: CVE Program / CVE List V5

Vulnerability Type

在Web页面生成时对输入的转义处理不恰当(跨站脚本)

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
cure53	DOMPurify	0 ~ 3.4.17	-

II. Public POCs for CVE-2026-116802

#	POC Description	Source Link	Shenlong Link

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No public POC found.

III. Intelligence Information for CVE-2026-116802

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Other References for CVE-2026-116802 (2)

https://github.com/cure53/DOMPurify/security/advisories/GHSA-c6gr-qvv4-5v3f vendor-advisory
https://www.vulncheck.com/advisories/dompurify-before-3.4.17-xss-via-smil-attributename-guard-bypass-in-xhtml-mode third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-116802

Same Patch Batch · cure53 · 2026-10-26 · 3 CVEs total

CVE-2026-116804	6.1 MEDIUM	DOMPurify from 3.4.4 before 3.4.17 SAFE_FOR_TEMPLATES Bypass via Shadow Root Content
CVE-2026-116803	6.1 MEDIUM	DOMPurify before 3.4.17 DOM XSS via IN_PLACE Hook-Detached Subtrees

IV. Related Vulnerabilities

Same product: DOMPurify

Same vendor: cure53

Same weakness: CWE-79