CVE-2026-50290
MediumCVSS 5.3Exploitation Probability (EPSS)
Low risk29th percentile - higher than 29% of all known CVEs
Summary
SpecifyJS is a declarative TypeScript user interface framework. Prior to version 0.2.136, CSS value sanitization stripped `expression(` and `url(javascript:` using simple regex, but could be bypassed with CSS unicode escapes (`\65xpression(`), null bytes, or CSS comments (`exp/**/ression(`). These CSS injection vectors only work in legacy browsers (IE6-IE10). SpecifyJS targets modern browsers. Starting in version 0.2.136, CSS sanitization now normalizes unicode escapes and strips CSS comments before pattern matching. Also checks for `behavior:`, `-moz-binding`, and `-o-link` patterns.
Risk Assessment
The risk is limited because the vectors only work in legacy browsers, but if the application is used in an environment with such browsers, CSS injection could lead to code execution or defacement. Update is recommended.
Recommendation
It is recommended to update SpecifyJS to version 0.2.136 or later, which includes the CSS sanitization fix. Also consider supporting only modern browsers.
Other vulnerabilities in SpecifyJS
Original NVD description (English source)
SpecifyJS is a declarative TypeScript user interface framework. Prior to version 0.2.136, CSS value sanitization stripped `expression(` and `url(javascript:` using simple regex, but could be bypassed with CSS unicode escapes (`\65xpression(`), null bytes, or CSS comments (`exp/**/ression(`). These CSS injection vectors only work in legacy browsers (IE6-IE10). SpecifyJS targets modern browsers. Starting in version 0.2.136, CSS sanitization now normalizes unicode escapes and strips CSS comments before pattern matching. Also checks for `behavior:`, `-moz-binding`, and `-o-link` patterns.