{"answers":{"affected":"4 open source packages ship an affected version, including undici. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-84961 in the wild and no public exploit code.","fix":"Upgrade undici to a fixed version for your release line: 7.29.1 or 8.10.2.","what":"CVE-2026-84961 is a high-severity vulnerability in Nodejs Undici, published on 4 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-2026-84961 and fix it if it is affected.\n\nWhat it is: CVE-2026-84961 is a high-severity vulnerability in Nodejs Undici, published on 4 Sep 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-2026-84961 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- undici (npm): affected from 7.24.1; fixed in 7.29.1\n- undici (npm): affected from 7.24.1; fixed in 7.29.1\n- undici (npm): affected from 8.0.0; fixed in 8.10.2\n- undici (npm): affected from 8.0.0; fixed in 8.10.2\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-2026-84961/ (Markdown: https://insights.sbomify.com/CVE-2026-84961/index.md)","id":"CVE-2026-84961","markdown":"https://insights.sbomify.com/CVE-2026-84961/index.md","name":"CVE-2026-84961","record":{"aliases":["CLEANSTART-2026-NT71796","CLEANSTART-2026-XJ20290","CLEANSTART-2026-XX88554","DEBIAN-CVE-2026-84961","ECHO-e485-5b9d-e4bc","GHSA-w293-vg96-wgc3","MINI-3745-p356-hj7j","MINI-3rq5-gf7g-xcrj","MINI-5324-pm2g-gfx4","MINI-5hcc-w4mv-59rf","MINI-6565-86jg-7585","MINI-83gv-5532-53jg","MINI-979f-jcqh-wj88","MINI-9qx9-4jjf-mwr4","MINI-cq23-f5gq-f3pc","MINI-cr5g-p6gv-788x","MINI-g834-cp5f-fpv2","MINI-m2cv-cw49-7h86","MINI-w855-7phh-qcmx","ROOT-APP-NPM-CVE-2026-84961","UBUNTU-CVE-2026-84961"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"Node.js HTTP client","requires_auth":"none","summary":"Attackers can bypass custom TLS certificate validation in undici's BalancedPool by exploiting a JSON serialization bug that drops function-based security checks.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"openjs","cpe":[{"product":"undici","vendor":"nodejs"}],"cvss":{"score":7.4,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-295","name":"Improper Certificate Validation"}],"description":"undici's BalancedPool constructor passes its entire options object through an internal deep-clone that serializes and reparses the value as JSON. Because JSON cannot represent functions, any function-valued TLS option, such as a caller-supplied checkServerIdentity callback or a custom connector inside the connect option, is silently discarded before it reaches the TLS layer. As a result a peer whose certificate the application's custom checkServerIdentity was written to reject, but which still passes Node's default hostname and chain checks, is accepted when reached through BalancedPool. The Client, Pool, and Agent dispatchers are not affected because they extract the connect and tls options before cloning. This affects undici versions from 7.24.1 up to 7.29.1 and from 8.0.0 up to 8.10.2, and only when the application supplies a function-valued connect or tls option to BalancedPool. Users should upgrade to undici 7.29.1 or 8.10.2.","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":"undici vulnerable to TLS certificate validation bypass via dropped connect options in BalancedPool","id":"CVE-2026-84961","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":"nodejs:undici","products":["nodejs:undici"],"type":"security_feature_bypass","year":"2026"},"n_packages":4,"n_references":2,"next":{"headline":"Authenticated KMS request forgery via CRLF injection in GCP key identifier strings","id":"CVE-2026-84962"},"packages":[{"ecosystem":"npm","fixed":["7.29.1"],"introduced":["7.24.1"],"last_affected":[],"package":"undici","purl":null,"source":"GHSA-w293-vg96-wgc3"},{"ecosystem":"npm","fixed":["7.29.1"],"introduced":["7.24.1"],"last_affected":[],"package":"undici","purl":"pkg:npm/undici","source":"GHSA-w293-vg96-wgc3"},{"ecosystem":"npm","fixed":["8.10.2"],"introduced":["8.0.0"],"last_affected":[],"package":"undici","purl":null,"source":"GHSA-w293-vg96-wgc3"},{"ecosystem":"npm","fixed":["8.10.2"],"introduced":["8.0.0"],"last_affected":[],"package":"undici","purl":"pkg:npm/undici","source":"GHSA-w293-vg96-wgc3"}],"prev":{"headline":"WP-Members Membership Plugin \u003c= 3.5.6 - Reflected Cross-Site Scripting","id":"CVE-2026-84960"},"products":["undici"],"published":"2026-09-04","related":[{"cvss_score":7.5,"headline":"undici WebSocket client vulnerable to Denial of Service via failed HTTP/2 handshake","id":"CVE-2026-109855","kev_date_added":null,"published":"2026-10-15"},{"cvss_score":7.5,"headline":"undici vulnerable to Denial of Service via unhandled error on excessive content-encodings","id":"CVE-2026-109869","kev_date_added":null,"published":"2026-10-15"},{"cvss_score":7.5,"headline":"undici vulnerable to Denial of Service via TLS 1.2 certificate-changing renegotiation","id":"CVE-2026-87018","kev_date_added":null,"published":"2026-10-15"},{"cvss_score":7.5,"headline":"undici vulnerable to Denial of Service via unrequested WebSocket subprotocol","id":"CVE-2026-19534","kev_date_added":null,"published":"2026-09-04"},{"cvss_score":7.5,"headline":"undici WebSocket client vulnerable to denial of service via fragment count bypass","id":"CVE-2026-12151","kev_date_added":null,"published":"2026-06-17"},{"cvss_score":7.5,"headline":"undici vulnerable to cross-origin request routing via SOCKS5 proxy pool reuse","id":"CVE-2026-6734","kev_date_added":null,"published":"2026-06-17"},{"cvss_score":7.5,"headline":"undici WebSocket client vulnerable to denial of service via cumulative fragment bypass","id":"CVE-2026-9675","kev_date_added":null,"published":"2026-06-17"}],"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":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-09-04","vendors":["undici"]},"summary":"Attackers can bypass custom TLS certificate validation in undici's BalancedPool by exploiting a JSON serialization bug that drops function-based security checks.","url":"https://insights.sbomify.com/CVE-2026-84961/"}