{"answers":{"affected":"2 open source packages ship an affected version, including undici. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-109855 in the wild and no public exploit code.","fix":"Upgrade undici to 8.11.2 or later.","what":"CVE-2026-109855 is a high-severity denial of service vulnerability in Nodejs Undici, published on 15 Oct 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-2026-109855 and fix it if it is affected.\n\nWhat it is: CVE-2026-109855 is a high-severity denial of service vulnerability in Nodejs Undici, published on 15 Oct 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-2026-109855 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- undici (npm): affected from 8.11.0; fixed in 8.11.2\n- undici (npm): affected from 8.11.0; fixed in 8.11.2\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-2026-109855/ (Markdown: https://insights.sbomify.com/CVE-2026-109855/index.md)","id":"CVE-2026-109855","markdown":"https://insights.sbomify.com/CVE-2026-109855/index.md","name":"CVE-2026-109855","record":{"aliases":["DEBIAN-CVE-2026-109855","ECHO-c178-9f2b-7f95","GHSA-qq8j-7v2v-3rwp","RHSA-2026:83198","ROOT-APP-NPM-CVE-2026-109855","UBUNTU-CVE-2026-109855"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Node.js HTTP client","requires_auth":"none","summary":"A malicious server can crash Node.js clients using undici's WebSocket over HTTP/2 by triggering an unhandled error on connection destruction.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"openjs","cpe":[{"product":"undici","vendor":"nodejs"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-754","name":"Improper Check for Unusual or Exceptional Conditions"},{"id":"CWE-248","name":"Uncaught Exception"}],"description":"undici is an HTTP client library for Node.js. In versions 8.11.0 and 8.11.1, its experimental WebSocket client, which is enabled by default when HTTP/2 is allowed, mishandles a failed WebSocket handshake over HTTP/2: the request is already marked completed, so the abort becomes a no-op and the underlying HTTP/2 stream is left open with no error listener. When a malicious server then destroys the connection, the orphaned stream emits an unhandled error and the Node.js process exits. A remote, unauthenticated server can therefore crash any client that opens a WebSocket to it over HTTP/2, resulting in a denial of service. The issue is fixed in undici 8.11.2, and users should upgrade to 8.11.2 or later. As a workaround, set allowH2 to false to disable HTTP/2 for WebSocket connections, or avoid opening WebSocket connections to untrusted servers.","ecosystems":["Red Hat:hummingbird:1","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 WebSocket client vulnerable to Denial of Service via failed HTTP/2 handshake","id":"CVE-2026-109855","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":"nodejs:undici","products":["nodejs:undici"],"type":"denial_of_service","year":"2026"},"n_packages":10,"n_references":2,"next":{"headline":"undici vulnerable to Denial of Service via unhandled error on excessive content-encodings","id":"CVE-2026-109869"},"packages":[{"ecosystem":"npm","fixed":["8.11.2"],"introduced":["8.11.0"],"last_affected":[],"package":"undici","purl":null,"source":"GHSA-qq8j-7v2v-3rwp"},{"ecosystem":"npm","fixed":["8.11.2"],"introduced":["8.11.0"],"last_affected":[],"package":"undici","purl":"pkg:npm/undici","source":"GHSA-qq8j-7v2v-3rwp"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:26.11.1-0.3.hum1"],"introduced":["0"],"last_affected":[],"package":"nodejs26","purl":"pkg:rpm/redhat/nodejs26","source":"RHSA-2026:83198"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:26.11.1-0.3.hum1"],"introduced":["0"],"last_affected":[],"package":"nodejs26-bin","purl":"pkg:rpm/redhat/nodejs26-bin","source":"RHSA-2026:83198"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:26.11.1-0.3.hum1"],"introduced":["0"],"last_affected":[],"package":"nodejs26-devel","purl":"pkg:rpm/redhat/nodejs26-devel","source":"RHSA-2026:83198"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:26.11.1-0.3.hum1"],"introduced":["0"],"last_affected":[],"package":"nodejs26-docs","purl":"pkg:rpm/redhat/nodejs26-docs","source":"RHSA-2026:83198"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:26.11.1-0.3.hum1"],"introduced":["0"],"last_affected":[],"package":"nodejs26-full-i18n","purl":"pkg:rpm/redhat/nodejs26-full-i18n","source":"RHSA-2026:83198"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:26.11.1-0.3.hum1"],"introduced":["0"],"last_affected":[],"package":"nodejs26-libs","purl":"pkg:rpm/redhat/nodejs26-libs","source":"RHSA-2026:83198"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:11.20.0-1.26.11.1.0.3.hum1"],"introduced":["0"],"last_affected":[],"package":"nodejs26-npm","purl":"pkg:rpm/redhat/nodejs26-npm","source":"RHSA-2026:83198"},{"ecosystem":"Red Hat:hummingbird:1","fixed":["0:26.11.1-0.3.hum1"],"introduced":["0"],"last_affected":[],"package":"nodejs26-npm-bin","purl":"pkg:rpm/redhat/nodejs26-npm-bin","source":"RHSA-2026:83198"}],"prev":{"headline":"M17n-lib: uninitialized stack read in iso-2022 compound text utf-8 decoding","id":"CVE-2026-109854"},"products":["undici"],"published":"2026-10-15","related":[{"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":"CC BY 4.0","name":"Red Hat","prefix":"RHSA"},{"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":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-15","vendors":["undici"]},"summary":"A malicious server can crash Node.js clients using undici's WebSocket over HTTP/2 by triggering an unhandled error on connection destruction.","url":"https://insights.sbomify.com/CVE-2026-109855/"}