{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-55517", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-06-16T22:44:22.284Z", "datePublished": "2026-06-23T17:24:59.498Z", "dateUpdated": "2026-06-23T17:52:56.960Z"}, "containers": {"cna": {"title": "Deno: Denial of service via non-ASCII bytes in WebSocket response headers", "problemTypes": [{"descriptions": [{"cweId": "CWE-248", "lang": "en", "description": "CWE-248: Uncaught Exception", "type": "CWE"}]}], "metrics": [{"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 4.3, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L", "version": "3.1"}}], "references": [{"name": "https://github.com/denoland/deno/security/advisories/GHSA-x2qc-cmh9-f4hf", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/denoland/deno/security/advisories/GHSA-x2qc-cmh9-f4hf"}], "affected": [{"vendor": "denoland", "product": "deno", "versions": [{"version": "< 2.7.5", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-06-23T17:24:59.498Z"}, "descriptions": [{"lang": "en", "value": "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."}], "source": {"advisory": "GHSA-x2qc-cmh9-f4hf", "discovery": "UNKNOWN"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-06-23T17:52:15.311461Z", "id": "CVE-2026-55517", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-23T17:52:56.960Z"}}]}}

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{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,2.7.5)"}}], "enrichment": {"confidence": 82.0, "confidence_source": "matching", "scores": [{"score": 82.0, "source": "matching"}]}, "original": {"product": "deno", "source": "cna", "vendor": "denoland"}, "product": "deno", "vendor": "deno"}], "created": "2026-06-23T19:30:04.660315+00:00", "updated": "2026-06-24T16:00:06.911353+00:00", "vendors": ["deno", "deno$PRODUCT$deno"]}