---
id: CVE-2026-50290
title: SpecifyJS is a declarative TypeScript user interface framework
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 (`\65xpressi…
severity: medium
cwe:
  - CWE-79
vendor: asymmetric-effort
product: '@asymmetric-effort/specifyjs'
affected:
  - '@asymmetric-effort/specifyjs < 0.2.136'
patched:
  - '@asymmetric-effort/specifyjs 0.2.136'
published: '2026-08-21'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T19:10:00.297'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-50290'
references:
  - url: >-
      https://github.com/asymmetric-effort/specifyjs/commit/25d1fb491d99479efdf501f5f75e0bb80c908f0a
    label: security-advisories@github.com
  - url: >-
      https://github.com/asymmetric-effort/specifyjs/security/advisories/GHSA-93q6-wwjh-jc6h
    label: security-advisories@github.com
  - url: 'https://github.com/advisories/GHSA-93q6-wwjh-jc6h'
tags:
  - nvd
  - ghsa
  - npm
epss: 0.00489
epssPercentile: 0.41904
ecosystem: npm
ingestedAt: '2026-07-02T19:41:50.952Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Package advisory (CVE-2026-50290)

Affected packages:

- `@asymmetric-effort/specifyjs < 0.2.136`

Patched in:

- `@asymmetric-effort/specifyjs 0.2.136`

Source: https://github.com/advisories/GHSA-93q6-wwjh-jc6h