{"affected":[{"product":"hono","source":"CNA: GitHub_M","vendor":"honojs","versions":[{"status":"affected","version":"< 4.13.16"}]}],"cveId":"CVE-2026-126357","cwes":["CWE-288"],"description":"Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.13.16, mount() and app.mount() can remove a dynamic mount prefix using the route-pattern length rather than the matched-prefix length, allowing a crafted path to be forwarded as a protected inner route while the outer application routes the original path. Since 4.12.21, rebuilding the forwarded URL from the decoded pathname can also convert a decoded backslash to a slash and collapse parent-directory segments, again causing the mounted application to receive a protected path. An unauthenticated client can use either applicable path transformation to reach a mounted route without authentication or authorization middleware scoped to a subpath inside the mount prefix. This issue is fixed in version 4.13.16.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":5.3,"severity":"medium","source":"CNA: GitHub_M","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"}],"modifiedAt":1794521926437,"publishedAt":1794521926437,"references":[{"source":"CNA: GitHub_M","tags":["x_refsource_CONFIRM"],"url":"https://github.com/honojs/hono/security/advisories/GHSA-4m76-xfj5-7975"},{"source":"CNA: GitHub_M","tags":["x_refsource_MISC"],"url":"https://github.com/honojs/hono/commit/34f90432a1794b28e52802670efcd01963f716d6"},{"source":"CNA: GitHub_M","tags":["x_refsource_MISC"],"url":"https://github.com/honojs/hono/releases/tag/v4.13.16"}],"remediation":[],"revision":"0400489866847a6ce253a1a78d1cf0f1510b7a59dceba11e02670df5490d6edd","sources":[{"modifiedAt":1794521926437,"name":"CNA: GitHub_M","retrievedAt":1794524923454,"url":"https://www.cve.org/CVERecord?id=CVE-2026-126357"}],"ssvc":null,"status":"published","title":"Hono: `mount()` and `app.mount()` can forward a path that bypasses middleware scoped inside the mount prefix","updatedAt":1794524923454}