Description
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in dashbitco lazy_html allows mutation XSS via a parse and serialize round-trip of attacker-supplied HTML. LazyHTML.to_html/2 and LazyHTML.Tree.to_html/2 decide whether to escape an element's text from its tag name alone. A style or script element inside SVG or MathML foreign content is parsed with character references decoded, but is serialized as an HTML raw-text element, so its text is emitted unescaped. Encoded markup such as </style><img src=x onerror=...> inside <svg><style> therefore closes the element on re-parse and becomes live markup. Applications that parse untrusted HTML with lazy_html, filter the document or tree, and serialize it for display are affected, since the payload is a plain text node that no element or attribute filter sees. This issue affects lazy_html: from 0.1.0 before 0.1.13.
References5
Metrics
- CVSS 4.0
-
2.3
LOW
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 34 · as of 9 November 2026
- CWE
- CWE-79
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.