{"id":"CVE-2026-55517","revision":"4c67d86fbe624733837fbf6f73edf044","records":[{"revision":"4c67d86fbe624733837fbf6f73edf044","observedAt":"2026-10-27T15:15:14.036+00:00","statement":{"source":"nvd","id":"CVE-2026-55517","aliases":[],"title":"Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.5, a Deno program that opens a client WebSocket connection could be crashed by the remote server. While handling the WebSocket handshake response, Deno parsed the Sec-W…","description":"Deno is a JavaScript, TypeScript, and WebAssembly runtime. Prior to 2.7.5, a Deno program that opens a client WebSocket connection could be crashed by the remote server. While handling the WebSocket handshake response, Deno parsed the Sec-WebSocket-Protocol and Sec-WebSocket-Extensions response headers in a way that assumed their bytes were always printable ASCII. A response header containing non-visible-ASCII bytes (0x80-0xFF) caused a panic that aborted the entire Deno process. This vulnerability is fixed in 2.7.5.","state":0,"publishedAt":"2026-06-23T18:18:09.787+00:00","modifiedAt":"2026-10-25T23:10:00.167+00:00","affected":[],"metrics":[{"system":"CVSS 3.1 · security-advisories@github.com · Secondary","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L","score":4.3,"severity":"MEDIUM"}],"references":["https://github.com/denoland/deno/security/advisories/GHSA-x2qc-cmh9-f4hf"],"sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-55517","license":"NIST NVD usage terms; underlying source attribution retained","enrichment":{"sourceStatus":"Analyzed","weaknesses":["CWE-248"],"productCriteria":["cpe:2.3:a:deno:deno:*:*:*:*:*:*:*:*"],"sourceDates":{"published":"2026-06-23T18:18:09.787","lastModified":"2026-10-25T23:10:00.167"},"relatedAdvisories":[],"note":"NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON."},"key":"nvd:CVE-2026-55517","identifiers":["CVE-2026-55517"]},"retained":false,"historicalAffected":[]}],"coverage":[]}