{"schema":"threatline.record/2","record":{"id":"CVE-2026-9675","aliases":["GHSA-38rv-x7px-6hhq"],"summary":"undici WebSocket client vulnerable to denial of service via cumulative fragment bypass","details":"## Impact\n\nThe undici WebSocket client enforces `maxPayloadSize` per-frame but does not enforce the cumulative size of fragmented uncompressed messages. A malicious WebSocket server can stream many small fragments that each pass per-frame validation but collectively exceed the configured limit, 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(...)`) that can be induced to connect to an attacker-controlled or compromised WebSocket endpoint.\n\nThis is a regression specific to undici 8.1.0. The 6.25.0 line shipped the equivalent cumulative check from the start and is unaffected. The 7.x line never had the `maxPayloadSize` feature and is also unaffected.\n\n## Patches\n\nUpgrade to undici >= 8.5.0.\n\n## Workarounds\n\nNo workaround is available. The fix must be applied through an upgrade.","categories":["Libraries & packages"],"product":"undici","vendor":"undici","ecosystem":"npm","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-38rv-x7px-6hhq","source_modified_at":"2026-10-22T05:07:56Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"undici"},"range":">= 8.0.0, < 8.5.0"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-9675","source_modified_at":"2026-06-17T17:29:42.926Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"undici","vendor":"undici","versions":[{"versionType":"semver","status":"affected","version":"8.0.0","lessThan":"8.5.0"},{"versionType":"semver","status":"unaffected","version":"8.5.0"}],"defaultStatus":"unaffected"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-38rv-x7px-6hhq","source_modified_at":"2026-06-18T14:41:29.213511Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"undici","purl":"pkg:npm/undici"},"ranges":[{"events":[{"introduced":"8.0.0"},{"fixed":"8.5.0"}],"type":"SEMVER"}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-38rv-x7px-6hhq","source_modified_at":"2026-10-22T05:07:56Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"undici"},"version":"8.5.0"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-9675","source_modified_at":"2026-06-17T17:29:42.926Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"undici","ecosystem":null},"version":"8.5.0","basis":"first unaffected version stated in the CVE record"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-38rv-x7px-6hhq","source_modified_at":"2026-06-18T14:41:29.213511Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"undici","purl":"pkg:npm/undici"},"version":"8.5.0"}],"cvss":7.5,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00488,"percentile":0.41101,"score_date":"2026-10-23"},"published_at":"2026-06-17T16:20:32.548Z","modified_at":"2026-10-22T05:07:56Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-38rv-x7px-6hhq","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-22T05:07:56Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-9675","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-06-17T17:29:42.926Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-38rv-x7px-6hhq","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-06-18T14:41:29.213511Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-9675","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["GitHub Advisory Database","CVE List","OSV","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/nodejs/undici/security/advisories/GHSA-38rv-x7px-6hhq"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-9675","source":"GitHub Advisory Database"},{"source":"CVE List","url":"https://cna.openjsf.org/security-advisories.html"},{"url":"https://github.com/advisories/GHSA-38rv-x7px-6hhq","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"none","automatable":"yes","technical_impact":"partial","assessed_at":"2026-06-17T17:29:24.751635Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-22T05:07:56Z","content_hash":"32792809e431b6b7ef0e1f885e1ce25dfc3f39c772a620cc6483443f52b31d96"}}