{"answers":{"affected":"4 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-2026-86252 exists.","fix":"Upgrade h3 to a fixed version for your release line: 1.15.9 or 2.0.1-rc.17.","what":"CVE-2026-86252 is a medium-severity 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-2026-86252 and fix it if it is affected.\n\nWhat it is: CVE-2026-86252 is a medium-severity 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-2026-86252 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- h3 (npm): affected from 2.0.0-beta.0; fixed in 2.0.1-rc.17\n- h3 (npm): affected from 2.0.0-beta.0; fixed in 2.0.1-rc.17\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-2026-86252/ (Markdown: https://insights.sbomify.com/CVE-2026-86252/index.md)","id":"CVE-2026-86252","markdown":"https://insights.sbomify.com/CVE-2026-86252/index.md","name":"CVE-2026-86252","record":{"aliases":["GHSA-4hxc-9384-m385","GHSA-jqj6-8hxr-7wwq"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["data_modify","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Node.js HTTP library","requires_auth":"none","summary":"Attackers can inject arbitrary Server-Sent Events by exploiting unsanitized carriage returns in h3 library data fields.","user_interaction":"not_required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[],"cvss":{"score":6.9,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-74","name":"Improper Neutralization of Special Elements in Output Used by a Downstream Component"}],"description":"h3 versions before 1.15.9 fail to sanitize carriage return characters in EventStream data and comment fields, allowing attackers to inject arbitrary SSE events by including unsanitized carriage returns. Attackers can inject event type directives, split single push calls into multiple browser-parsed events, or escape comment fields to inject data, bypassing the prior CVE fix that only addressed newline injection.","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 SSE Event Injection via Carriage Return","id":"CVE-2026-86252","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"other","year":"2026"},"n_packages":4,"n_references":2,"next":{"headline":"h3 before 1.15.6 Path Traversal via Percent-Encoded Dot Segments","id":"CVE-2026-86253"},"packages":[{"ecosystem":"npm","fixed":["1.15.9"],"introduced":["0"],"last_affected":[],"package":"h3","purl":null,"source":"GHSA-4hxc-9384-m385"},{"ecosystem":"npm","fixed":["1.15.9"],"introduced":["0"],"last_affected":[],"package":"h3","purl":"pkg:npm/h3","source":"GHSA-4hxc-9384-m385"},{"ecosystem":"npm","fixed":["2.0.1-rc.17"],"introduced":["2.0.0-beta.0"],"last_affected":[],"package":"h3","purl":null,"source":"GHSA-4hxc-9384-m385"},{"ecosystem":"npm","fixed":["2.0.1-rc.17"],"introduced":["2.0.0-beta.0"],"last_affected":[],"package":"h3","purl":"pkg:npm/h3","source":"GHSA-4hxc-9384-m385"}],"prev":{"headline":"h3 before 1.15.9 Path Traversal via Double Decoding","id":"CVE-2026-86251"},"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":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-09-08","vendors":["h3js"]},"summary":"Attackers can inject arbitrary Server-Sent Events by exploiting unsanitized carriage returns in h3 library data fields.","url":"https://insights.sbomify.com/CVE-2026-86252/"}