{"cve":"CVE-2026-12151","nvd":{"published":"2026-06-17T17:16:42.370","modified":"2026-09-11T13:17:05.943","status":"Modified","description":"Impact:\nThe undici WebSocket client enforces maxPayloadSize on the cumulative byte count of fragments in a message but does not enforce a limit on the number of fragments. A malicious WebSocket server can stream many small or empty continuation frames that each pass per-frame and cumulative-size validation, collectively causing unbounded memory growth in the client process. The result is memory exhaustion and a denial of service.\n\nAffected applications are those using the undici WebSocket client (new WebSocket(...)) or the WebSocketStream API that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint.\n\nAll releases starting at undici 6.17.0 are affected.\n\nPatches: Upgrade to undici >= 6.26.0, >= 7.28.0, or >= 8.5.0. Workarounds:\nNo workaround is available. The fix must be applied through an upgrade.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-400","CWE-770"],"references":["https://cna.openjsf.org/security-advisories.html","https://github.com/nodejs/undici/security/advisories/GHSA-vxpw-j846-p89q","https://access.redhat.com/errata/RHSA-2026:34342","https://access.redhat.com/errata/RHSA-2026:35841","https://access.redhat.com/errata/RHSA-2026:35842"],"products":["nodejs:undici"],"source":"nvd","synced_at":"2026-10-19T22:39:28.638635428+00:00"},"epss":{"cve":"CVE-2026-12151","score":0.00789,"percentile":0.56236,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-vxpw-j846-p89q","url":"https://osv.dev/vulnerability/GHSA-vxpw-j846-p89q","summary":"undici WebSocket client vulnerable to denial of service via fragment count bypass","modified":"2026-09-10T03:50:12.291121037Z","packages":[{"ecosystem":"npm","name":"undici","purl":"pkg:npm/undici","ranges":["<6.27.0"],"fixed":["6.27.0"]},{"ecosystem":"npm","name":"undici","purl":"pkg:npm/undici","ranges":[">=7.0.0 <7.28.0"],"fixed":["7.28.0"]},{"ecosystem":"npm","name":"undici","purl":"pkg:npm/undici","ranges":[">=8.0.0 <8.5.0"],"fixed":["8.5.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}