{"answers":{"affected":"2 open source packages ship an affected version, including h3.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86251 exists.","fix":"Upgrade h3 to 1.15.9 or later.","what":"CVE-2026-86251 is a high-severity path traversal vulnerability in h3js h3, published on 6 Sep 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-2026-86251 and fix it if it is affected.\n\nWhat it is: CVE-2026-86251 is a high-severity path traversal vulnerability in h3js h3, published on 6 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-86251 exists.\n\nAffected packages and fixed versions:\n- h3 (npm): affected all versions; fixed in 1.15.9\n- h3 (npm): affected all versions; fixed in 1.15.9\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.\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-2026-86251/ (Markdown: https://insights.sbomify.com/CVE-2026-86251/index.md)","id":"CVE-2026-86251","markdown":"https://insights.sbomify.com/CVE-2026-86251/index.md","name":"CVE-2026-86251","record":{"aliases":["GHSA-676v-2c25-vqpj","GHSA-72gr-qfp7-vwhw"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"h3 HTTP library","requires_auth":"none","summary":"Attackers can read arbitrary files from backend storage via double-encoded path traversal in the h3 serveStatic utility.","user_interaction":"not_required","vuln_class":"path_traversal"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[],"cvss":{"score":8.2,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-22","name":"Improper Limitation of a Pathname to a Restricted Directory"}],"description":"h3 versions before 1.15.9 contain a path traversal vulnerability in the serveStatic utility. A double-decoding flaw allows a request path containing double-encoded dot sequences (e.g. %252e%252e) to be decoded to %2e%2e, which survives resolveDotSegments() because that function only checks for literal '.' characters. When the resulting asset ID is resolved by URL-based backends (CDN, S3, object storage), %2e%2e is interpreted as '..' per RFC 3986, enabling path traversal to read arbitrary files from the backend.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":false,"headline":"h3 before 1.15.9 Path Traversal via Double Decoding","id":"CVE-2026-86251","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"path_traversal","year":"2026"},"n_packages":2,"n_references":2,"next":{"headline":"h3 before 1.15.9 SSE Event Injection via Carriage Return","id":"CVE-2026-86252"},"packages":[{"ecosystem":"npm","fixed":["1.15.9"],"introduced":["0"],"last_affected":[],"package":"h3","purl":null,"source":"GHSA-72gr-qfp7-vwhw"},{"ecosystem":"npm","fixed":["1.15.9"],"introduced":["0"],"last_affected":[],"package":"h3","purl":"pkg:npm/h3","source":"GHSA-72gr-qfp7-vwhw"}],"prev":{"headline":"h3 before 2.0.1-rc.18 Denial of Service via Unbounded Chunked Cookie","id":"CVE-2026-86250"},"products":["h3"],"published":"2026-09-06","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":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-09","vendors":["h3js"]},"summary":"Attackers can read arbitrary files from backend storage via double-encoded path traversal in the h3 serveStatic utility.","url":"https://insights.sbomify.com/CVE-2026-86251/"}