{"id":"CVE-2026-50290","aliases":["EUVD-2026-64123","GHSA-93q6-wwjh-jc6h"],"status":"published","title":"@asymmetric-effort/specifyjs: CSS expression sanitization is bypassable in renderToString","description":"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.","severity":{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00489,"percentile":0.42397,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-79"],"published":"2026-07-02T19:08:45Z","modified":"2026-10-28T02:30:29Z","fixes":[{"ecosystem":"npm","package":"@asymmetric-effort/specifyjs","fixed_in":["0.2.136"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@asymmetric-effort/specifyjs","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.2.136"}]}]},{"source":"osv","ecosystem":"npm","package":"@asymmetric-effort/specifyjs","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.2.136"}]}]}],"products":[{"vendor":"asymmetric-effort","product":"specifyjs"}],"references":[{"url":"https://github.com/asymmetric-effort/specifyjs/security/advisories/GHSA-93q6-wwjh-jc6h","tags":["x_refsource_CONFIRM","advisory","web"]},{"url":"https://github.com/asymmetric-effort/specifyjs/commit/25d1fb491d99479efdf501f5f75e0bb80c908f0a","tags":["x_refsource_MISC","fix","web"]},{"url":"https://github.com/advisories/GHSA-93q6-wwjh-jc6h"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/50xxx/CVE-2026-50290.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50290","tags":["advisory"]},{"url":"https://github.com/asymmetric-effort/specifyjs","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-50290","title":"@asymmetric-effort/specifyjs: CSS expression sanitization is bypassable in renderToString","description":"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.","status":"published","published":"2026-08-21T19:55:51.086Z","modified":"2026-08-21T20:07:10.712Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:20:08.734143Z"}],"euvd":[{"id":"EUVD-2026-64123","description":"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.","status":"published","published":"2026-08-21T19:55:51Z","modified":"2026-08-21T20:07:10Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"updated_at":"2026-11-02T18:01:36.844009Z"}],"ghsa":[{"id":"GHSA-93q6-wwjh-jc6h","title":"@asymmetric-effort/specifyjs: CSS expression sanitization is bypassable in renderToString","description":"## Finding\n\n**Location**: `core/src/server/render-to-string.ts:307-311`\n\nCSS 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(`).\n\n**Mitigating Factor**: These CSS injection vectors only work in legacy browsers (IE6-IE10). SpecifyJS targets modern browsers.\n\n## Status\n\n**Fixed in v0.2.136** — CSS sanitization now normalizes unicode escapes and strips CSS comments before pattern matching. Also checks for `behavior:`, `-moz-binding`, and `-o-link` patterns.","status":"published","published":"2026-07-02T19:08:45Z","modified":"2026-07-02T19:08:46Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:40:37.437888Z"}],"nvd":[{"id":"CVE-2026-50290","description":"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.","status":"published","published":"2026-08-21T20:16:36.22Z","modified":"2026-10-14T19:10:00.297Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/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","level":"medium","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:40.665005Z"}],"osv":[{"id":"CVE-2026-50290","title":"@asymmetric-effort/specifyjs: CSS expression sanitization is bypassable in renderToString","description":"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.","status":"published","published":"2026-08-21T19:55:51.086Z","modified":"2026-10-28T02:30:29.961547427Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:07.431113Z"},{"id":"GHSA-93q6-wwjh-jc6h","title":"@asymmetric-effort/specifyjs: CSS expression sanitization is bypassable in renderToString","description":"## Finding\n\n**Location**: `core/src/server/render-to-string.ts:307-311`\n\nCSS 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(`).\n\n**Mitigating Factor**: These CSS injection vectors only work in legacy browsers (IE6-IE10). SpecifyJS targets modern browsers.\n\n## Status\n\n**Fixed in v0.2.136** — CSS sanitization now normalizes unicode escapes and strips CSS comments before pattern matching. Also checks for `behavior:`, `-moz-binding`, and `-o-link` patterns.","status":"published","published":"2026-07-02T19:08:45Z","modified":"2026-09-10T03:51:11.288040472Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:43.123867Z"}]}}