{"id":"CVE-2026-59895","state":"PUBLISHED","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.","publishedAt":"2026-07-08T16:09:51.273Z","updatedAt":"2026-07-08T19:41:04.292Z","severity":{"score":6.1,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["honojs hono"],"affected":[{"vendor":"honojs","product":"hono","versions":[{"version":">= 4.0.0, < 4.12.27","status":"affected"}]}],"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"],"weaknesses":["CWE-79","CWE-116"],"ingestedAt":"2026-10-29T20:12:32.778Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/59xxx/CVE-2026-59895.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-59895","state":"PUBLISHED","datePublished":"2026-07-08T16:09:51.273Z","dateUpdated":"2026-07-08T19:41:04.292Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-07T16:40:07.983Z"},"containers":{"cna":{"title":"Hono: Server-Side XSS via JSX Escaping Bypass in cx() Utility","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"honojs","product":"hono","versions":[{"version":">= 4.0.0, < 4.12.27","status":"affected"}]}],"references":[{"url":"https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59","name":"https://github.com/honojs/hono/security/advisories/GHSA-w62v-xxxg-mg59","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fc","name":"https://github.com/honojs/hono/commit/cd3f6f7194f0e5c9d4b26ae0cf232018d0f388fc","tags":["x_refsource_MISC"]},{"url":"https://github.com/honojs/hono/releases/tag/v4.12.27","name":"https://github.com/honojs/hono/releases/tag/v4.12.27","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.1,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-116","lang":"en","description":"CWE-116: Improper Encoding or Escaping of Output","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-07-08T16:09:51.273Z"},"source":{"advisory":"GHSA-w62v-xxxg-mg59","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-08T17:50:18.277447Z","id":"CVE-2026-59895","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-08T19:41:04.292Z"}}]}}}