{"id":"GHSA-qp7p-654g-cw7p","summary":"Hono has CSS Declaration Injection via Style Object Values in JSX SSR","details":"### Summary\n\nThe JSX renderer escapes `style` attribute object values for HTML but not for CSS. Untrusted input in a `style` object value or property name can therefore inject additional CSS declarations into the rendered `style` attribute. The impact is limited to CSS and does not allow JavaScript execution or HTML attribute breakout.\n\n### Details\n\n`style` object values are serialized into a CSS declaration list and escaped for HTML attribute context only. Characters that act as CSS declaration boundaries — such as `;`, comment markers, quoted strings, and block delimiters — are valid in HTML attribute content and can extend a value beyond its assigned property.\n\nThis issue arises when untrusted input is interpolated into a JSX `style` object and rendered server-side.\n\n### Impact\n\nAn attacker who can control the value or property name of a `style` object may inject arbitrary CSS declarations. This may lead to:\n\n- Visual manipulation of the page, including full-viewport overlays usable for phishing\n- Outbound requests to attacker-controlled hosts via CSS resource references such as `url(...)`\n- Hijacking of UI affordances through layout, positioning, or visibility changes\n\nThis issue affects applications that render JSX on the server with `style` object values or property names derived from untrusted input.","aliases":["CVE-2026-44458"],"modified":"2026-07-17T21:17:00.247197963Z","published":"2026-05-09T00:46:44Z","database_specific":{"cwe_ids":["CWE-116","CWE-74"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-05-09T00:46:44Z","nvd_published_at":null},"references":[{"type":"WEB","url":"https://github.com/honojs/hono/security/advisories/GHSA-qp7p-654g-cw7p"},{"type":"PACKAGE","url":"https://github.com/honojs/hono"}],"affected":[{"package":{"name":"hono","ecosystem":"npm","purl":"pkg:npm/hono"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"4.12.18"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-qp7p-654g-cw7p/GHSA-qp7p-654g-cw7p.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"}]}