{"answers":{"affected":"1 open source package ship an affected version, including hono.","exploited":"There is no known exploitation of CVE-2026-126357 in the wild and no public exploit code.","exposure":"An affected version is only exploitable if your software calls mount() or app.mount(). Many projects that include it are not exposed.","fix":"Upgrade hono to 4.13.16 or later.","what":"CVE-2026-126357 is a medium-severity authentication bypass vulnerability in honojs hono, published on 12 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-126357 and fix it if it is affected.\n\nWhat it is: CVE-2026-126357 is a medium-severity authentication bypass vulnerability in honojs hono, published on 12 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2026-126357 in the wild and no public exploit code.\nExposure: An affected version is only exploitable if your software calls mount() or app.mount(). Many projects that include it are not exposed.\n\nAffected packages and fixed versions:\n- hono (npm): affected all versions; fixed in 4.13.16\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n   If an affected version is present, also search the code for calls to mount() or app.mount() and report whether any exist.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-126357/ (Markdown: https://insights.sbomify.com/CVE-2026-126357/index.md)","id":"CVE-2026-126357","markdown":"https://insights.sbomify.com/CVE-2026-126357/index.md","name":"CVE-2026-126357","record":{"aliases":["GHSA-4m76-xfj5-7975"],"analysis":{"component_type":"library","exploitable_when_present":false,"fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"JavaScript web framework","requires_auth":"none","requires_specific_call":true,"summary":"Unauthenticated clients can reach protected inner routes in Hono apps using mount() by bypassing scoped middleware.","user_interaction":"not_required","vuln_class":"auth_bypass","vulnerable_functions":["mount()","app.mount()"]},"analysis_generated_by":"sbomify/insights-2b-fp8","assigner":"GitHub_M","cpe":[],"cvss":{"score":5.3,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-288","name":"Authentication Bypass Using an Alternate Path or Channel"}],"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.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Hono: `mount()` and `app.mount()` can forward a path that bypasses middleware scoped inside the mount prefix","id":"CVE-2026-126357","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"auth_bypass","year":"2026"},"n_packages":1,"n_references":3,"next":{"headline":"Hono: RegExpRouter skips wildcard middleware for some route sets and for paths with an encoded line terminator","id":"CVE-2026-126358"},"nickname":null,"packages":[{"ecosystem":"npm","fixed":["4.13.16"],"introduced":["0"],"last_affected":[],"package":"hono","purl":null,"source":"GHSA-4m76-xfj5-7975"}],"prev":{"headline":"Hono: `validator('form')` skips validation for `multipart/form-data` requests with extra parameters","id":"CVE-2026-126356"},"products":["hono"],"published":"2026-11-12","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-11-12","vendors":["honojs"]},"summary":"Unauthenticated clients can reach protected inner routes in Hono apps using mount() by bypassing scoped middleware.","url":"https://insights.sbomify.com/CVE-2026-126357/"}