rrrene html_sanitize_ex up to 1.5.2 HTML5 Scrubber html5.ex HTML injection

Summaryinfo

A vulnerability classified as problematic was found in rrrene html_sanitize_ex up to 1.5.2. This affects an unknown part of the file lib/html_sanitize_ex/scrubber/html5.ex of the component HTML5 Scrubber. The manipulation results in HTML injection. This vulnerability is reported as CVE-2026-66843. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as problematic, was found in rrrene html_sanitize_ex up to 1.5.2. Affected is an unknown function of the file lib/html_sanitize_ex/scrubber/html5.ex of the component HTML5 Scrubber. The manipulation with an unknown input leads to a html injection vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to load a document of their choosing into a trusted page via the data attribute of an <object> element in sanitized HTML. object is the one URI-bearing element in lib/html_sanitize_ex/scrubber/html5.ex never registered through allow_tag_with_uri_attributes/3, and its only guard is a prefix match on lowercase "javascript:", so mixed-case variants, data: URIs, protocol-relative URLs and same-origin paths all survive. This is not unconditional cross-site scripting. A javascript: URL does not execute through <object data> in current browsers, data: documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path. This issue affects html_sanitize_ex: from 0.3.1 before 1.5.3.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-66843 since 08/06/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 1.5.3 eliminates this vulnerability.

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Productinfo

Vendor

• rrrene

Name

• html_sanitize_ex

Version

• 1.5.0
• 1.5.1
• 1.5.2

Website

• Product: https://github.com/rrrene/html_sanitize_ex/

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