{"id":"CVE-2026-59895","revision":null,"records":[{"revision":"4e0b198b33e842f99d546d081bdb0958","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-59895","aliases":[],"title":"Hono: Server-Side XSS via JSX Escaping Bypass in cx() Utility","description":"Hono is a Web application framework that provides support for any JavaScript runtime. From 4.0.0 before 4.12.27, cx() in hono/css composes class names from plain strings but marks the result as already escaped without HTML-escaping the input, allowing untrusted className values used in a JSX class attribute during server-side rendering to break out of the attribute and inject arbitrary markup. This issue is fixed in version 4.12.27.","state":0,"publishedAt":"2026-07-08T16:09:51.273+00:00","modifiedAt":"2026-07-08T19:41:04.292+00:00","affected":[{"ecosystem":"Vendor product","name":"hono","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"honojs\",\n                    \"product\": \"hono\",\n                    \"versions\": [\n                        {\n                            \"version\": \">= 4.0.0, < 4.12.27\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1,"severity":"MEDIUM"}],"references":["https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59","https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fc","https://github.com/honojs/hono/releases/tag/v4.12.27"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-59895","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-59895","identifiers":["CVE-2026-59895"]},"retained":false,"historicalAffected":[]},{"revision":"8c60865b1c124ec59638958f75a46356","observedAt":"2026-11-07T13:26:04.613+00:00","statement":{"source":"euvd","id":"EUVD-2026-42327","aliases":["CVE-2026-59895","GHSA-w62v-xxxg-mg59"],"title":"Hono is a Web application framework that provides support for any JavaScript runtime. From 4.0.0 before 4.12.27, cx() in hono/css composes class names from plain strings but marks the result as already escaped without HTML-escaping the inpu…","description":"Hono is a Web application framework that provides support for any JavaScript runtime. From 4.0.0 before 4.12.27, cx() in hono/css composes class names from plain strings but marks the result as already escaped without HTML-escaping the input, allowing untrusted className values used in a JSX class attribute during server-side rendering to break out of the attribute and inject arbitrary markup. This issue is fixed in version 4.12.27.","state":0,"publishedAt":null,"modifiedAt":null,"affected":[],"metrics":[{"system":"EUVD CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1,"severity":null}],"references":["https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59","https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fc","https://github.com/honojs/hono/releases/tag/v4.12.27"],"sourceUrl":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-42327","license":"ENISA EUVD · source terms and attribution apply","enrichment":{"sourceStatus":null,"weaknesses":[],"productCriteria":[],"sourceDates":{"datePublished":"Jul 8, 2026, 4:09:51 PM","dateUpdated":"Jul 8, 2026, 7:41:04 PM"},"relatedAdvisories":[],"note":"EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON."},"key":"euvd:EUVD-2026-42327","identifiers":["EUVD-2026-42327","CVE-2026-59895","GHSA-w62v-xxxg-mg59"]},"retained":false,"historicalAffected":[]},{"revision":"9900284ad4974813b4c231e8f1e57217","observedAt":"2026-10-27T15:15:33.457+00:00","statement":{"source":"nvd","id":"CVE-2026-59895","aliases":[],"title":"Hono is a Web application framework that provides support for any JavaScript runtime. From 4.0.0 before 4.12.27, cx() in hono/css composes class names from plain strings but marks the result as already escaped without HTML-escaping the inpu…","description":"Hono is a Web application framework that provides support for any JavaScript runtime. From 4.0.0 before 4.12.27, cx() in hono/css composes class names from plain strings but marks the result as already escaped without HTML-escaping the input, allowing untrusted className values used in a JSX class attribute during server-side rendering to break out of the attribute and inject arbitrary markup. This issue is fixed in version 4.12.27.","state":0,"publishedAt":"2026-07-08T17:17:27.353+00:00","modifiedAt":"2026-10-25T17:10:00.197+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1,"severity":"MEDIUM"}],"references":["https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fc","https://github.com/honojs/hono/releases/tag/v4.12.27","https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-59895","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-79","CWE-116"],"productCriteria":["cpe:2.3:a:hono:hono:*:*:*:*:*:node.js:*:*"],"sourceDates":{"published":"2026-07-08T17:17:27.353","lastModified":"2026-10-25T17:10:00.197"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-59895","identifiers":["CVE-2026-59895"]},"retained":false,"historicalAffected":[]},{"revision":"7a0fb76e19824ae589c9f41708699a6b","observedAt":"2026-10-24T13:17:17.793+00:00","statement":{"source":"osv","id":"GHSA-w62v-xxxg-mg59","aliases":["CVE-2026-59895"],"title":"Hono: Server-Side XSS via JSX Escaping Bypass in cx() Utility","description":"### Summary\n\n`cx()` in `hono/css` composes class names from plain strings but marks the result as already-escaped without HTML-escaping the input. When the result is used as a JSX `class` attribute during server-side rendering, the value is written into the attribute unescaped, so untrusted input can break out of the `class` attribute and inject arbitrary markup, leading to Cross-Site Scripting (XSS).\n\n### Details\n\nBecause the composed value is treated as pre-escaped, the HTML attribute escaping normally applied to interpolated values is skipped, and characters such as `\"` pass through unescaped — allowing a value to terminate the attribute and add further attributes or elements. This arises when an application passes untrusted, user-controlled input as a class name to `cx()`, for example when merging a base class with an externally provided `className`.\n\n### Impact\n\nDuring server-side rendering, an attacker who controls a value passed to `cx()` can inject arbitrary HTML into the page, resulting in stored or reflected XSS in the victim's browser.\n\nThis may lead to:\n\n- Execution of attacker-controlled script in the victim's browser session.\n- Session hijacking, credential theft, or actions performed on behalf of the victim.\n\nApplications are affected only if they render JSX server-side and pass untrusted input as a class name to `cx()`.","state":0,"publishedAt":"2026-07-21T18:33:50+00:00","modifiedAt":"2026-09-10T03:51:12.3715078+00:00","affected":[{"ecosystem":"npm","name":"hono","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"4.0.0"},{"kind":"fixed","version":"4.12.27"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"MODERATE"}],"references":["https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59","https://nvd.nist.gov/vuln/detail/CVE-2026-59895","https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fc","https://github.com/honojs/hono","https://github.com/honojs/hono/releases/tag/v4.12.27"],"sourceUrl":"https://github.com/advisories/GHSA-w62v-xxxg-mg59","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-w62v-xxxg-mg59","identifiers":["GHSA-w62v-xxxg-mg59","CVE-2026-59895"]},"retained":false,"historicalAffected":[]}],"coverage":[{"source":"cisa-kev:global","scope":"Complete CISA KEV catalog; all vendors. Missing entries do not establish absence of exploitation.","generation":"2026-11-07T20:52:46.7845564+00:00","complete":true,"records":1769,"lastAttemptAt":"2026-11-07T20:52:46.7845564+00:00","lastSuccessAt":"2026-11-07T20:52:46.9707302+00:00","error":null,"lastVerifiedAt":"2026-11-07T20:52:46.9707321+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"cve-program","scope":"Official CVE Program baseline and cumulative hourly delta; all vendors, published and rejected records","generation":"cve-bb5c9d5a08063ef076042e33dd72a7d0ffa4c4487efdcf3106e29ba55ec2ad57-1766179264875bb4621a23ce4c6bcebec63fb794a16e35c2f5592f4ee300ee2e","complete":true,"records":420944,"lastAttemptAt":"2026-11-07T20:52:46.1142943+00:00","lastSuccessAt":"2026-11-07T20:52:46.0341312+00:00","error":null,"lastVerifiedAt":"2026-11-07T20:52:46.1142943+00:00","snapshotPublishedAt":"2026-11-07T20:26:36+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"euvd","scope":"Rolling EUVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global EUVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-cbfb00168958467aaa6015d5230faa08","complete":true,"records":13633,"lastAttemptAt":"2026-11-07T21:04:54.6100336+00:00","lastSuccessAt":"2026-11-07T21:04:54.606+00:00","error":null,"lastVerifiedAt":"2026-11-07T21:04:54.606+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13685,"expectedIdentifiers":13685,"failedIdentifiers":0},{"source":"first-epss:nuget","scope":"FIRST EPSS for explicit CVE aliases in the collected public NuGet archive. Not a global EPSS backfill.","generation":"2026-11-07T20:52:46.7845564+00:00","complete":true,"records":1096,"lastAttemptAt":"2026-11-07T20:52:46.7845564+00:00","lastSuccessAt":"2026-11-07T20:52:47.1482288+00:00","error":null,"lastVerifiedAt":"2026-11-07T20:52:47.1482303+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"nvd","scope":"Rolling NVD lookups of CVE aliases in current public OSV archives; 500 identifiers per refresh, rechecked after 48 hours. Not a global NVD catalog. Successful not-found lookups count as checked; they do not imply withdrawal or safety. No reader inventory is sent.","generation":"enrichment-b9464f9c589b4886928e7045b5ad1e11","complete":true,"records":13645,"lastAttemptAt":"2026-11-07T20:52:54.6850231+00:00","lastSuccessAt":"2026-11-07T20:52:54.68+00:00","error":null,"lastVerifiedAt":"2026-11-07T20:52:54.68+00:00","snapshotPublishedAt":null,"importing":false,"stagedRecords":0,"checkedIdentifiers":13685,"expectedIdentifiers":13685,"failedIdentifiers":0},{"source":"osv:Go","scope":"Complete OSV Go ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"go-0eb4d6dde62dffacd040ad992d4fd5a65cd7d0dc5f5f4cfa8b41967fc6f9ca5f","complete":true,"records":9914,"lastAttemptAt":"2026-11-07T20:52:46.6024506+00:00","lastSuccessAt":"2026-11-06T20:10:36.6450506+00:00","error":null,"lastVerifiedAt":"2026-11-07T20:52:46.6024506+00:00","snapshotPublishedAt":"2026-11-06T20:02:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:NuGet","scope":"Complete OSV NuGet ecosystem archive, including GitHub Advisory Database records; NuGet version matching only","generation":"nuget-fde804134ecdda0ddd5ff5c26ee1fff5a6fa659311f7ef2e51c6ad54964db0e2","complete":true,"records":1971,"lastAttemptAt":"2026-11-07T20:52:46.3552169+00:00","lastSuccessAt":"2026-11-06T19:03:17.0399903+00:00","error":null,"lastVerifiedAt":"2026-11-07T20:52:46.3552169+00:00","snapshotPublishedAt":"2026-11-06T18:17:57+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:crates.io","scope":"Complete OSV crates.io ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"crates.io-335633e78a15c9cde10a6025895b5617717087fb945489ae7e15d377bacf34a9","complete":true,"records":3055,"lastAttemptAt":"2026-11-07T20:52:46.7261257+00:00","lastSuccessAt":"2026-11-06T16:03:00.7615789+00:00","error":null,"lastVerifiedAt":"2026-11-07T20:52:46.7261257+00:00","snapshotPublishedAt":"2026-11-06T16:02:48+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null},{"source":"osv:npm","scope":"Complete OSV npm ecosystem archive, including withdrawn and malicious-package source records; statement counts are not unique CVE counts","generation":"npm-40ad6183a951565ace1520a9b4d631e1d0bfb1d4bf7c5574c375032559f3ff53","complete":true,"records":231292,"lastAttemptAt":"2026-11-07T20:52:46.4923243+00:00","lastSuccessAt":"2026-11-07T10:29:00.4821259+00:00","error":null,"lastVerifiedAt":"2026-11-07T20:52:46.4923243+00:00","snapshotPublishedAt":"2026-11-07T09:32:47+00:00","importing":false,"stagedRecords":0,"checkedIdentifiers":null,"expectedIdentifiers":null,"failedIdentifiers":null}]}