CVE-2026-44644: LiquidJS's strip_html filter bypass via newline characters in HTML tags enables XSS

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-17 · updated 2026-10-26
Weakness: CWE-79

Description

LiquidJS is a Shopify/GitHub Pages compatible template engine written in pure JavaScript. Versions 10.25.7 and below are vulnerable to XSS through a flaw in the strip_html filter logic. The strip_html filter is intended to remove HTML tags from a string before rendering, and is widely used as an XSS sanitizer. The implementation uses a regex whose catch-all branch (<.*?>) does not match line terminators, so any HTML tag containing a \n or \r character passes through unmodified. An attacker who can place a newline inside a tag (e.g. <img\nsrc=x\nonerror=alert(1)>) bypasses sanitization entirely, since browsers treat newlines as whitespace within a tag and execute the resulting onerror/onload/etc. handler. Exploitation is possible for applications that both render attacker-controlled strings via {{ x | strip_html }} to defend against HTML injection and do not separately HTML-escape that output (default behavior — outputEscape is unset by default). This issue has been fixed in version 10.26.0.

Affected products

harttle liquidjs: before 10.26.0

References

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