{"schema":"threatline.record/2","record":{"id":"CVE-2026-109924","aliases":["GHSA-4qv8-2p9j-2685"],"summary":"undici vulnerable to Denial of Service via unbounded memory in the EventSource parser","details":"### Impact\n\nundici's `EventSource` client can be driven to exhaust process memory by a malicious or compromised Server-Sent Events peer. By sending millions of tiny completed `data:` fields with no blank event separator, or a single unfinished line split across many chunks, the parser retains a growing amount of per-field and per-chunk state. The byte-based `maxEventSize` and `maxResponseSize` limits do not bound that retained state, and `maxResponseSize` is enforced on the compressed body before decompression, so a small compressed response can expand into enough retained memory to terminate the process. The application only needs to maintain an `EventSource` connection to an untrusted peer, which controls only the response. Availability is the only impact.\n\n### Patches\n\nUpgrade to `6.29.1`, `7.30.1`, or `8.12.2`, which bound the retained EventSource parser state (the number of `data` fields and buffered chunks, the unfinished-line length, and per-field byte totals) independently of the byte limits.\n\n### Workarounds\n\nNone.","categories":["Libraries & packages"],"product":"undici","vendor":"undici","ecosystem":"npm","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:13:31Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"ecosystem":"npm","name":"undici"},"range":">= 6.5.0, < 6.29.1"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:13:31Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"ecosystem":"npm","name":"undici"},"range":">= 7.0.0, < 7.30.1"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:13:31Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"ecosystem":"npm","name":"undici"},"range":">= 8.0.0, < 8.12.2"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-109924","source_modified_at":"2026-10-16T20:05:22.386Z","fetched_at":"2026-10-23T18:48:36.087640Z","product":"undici","vendor":"undici","versions":[{"lessThan":"6.29.1","status":"affected","version":"6.5.0","versionType":"semver"},{"status":"unaffected","version":"6.29.1","versionType":"semver"},{"lessThan":"7.30.1","status":"affected","version":"7.0.0","versionType":"semver"},{"status":"unaffected","version":"7.30.1","versionType":"semver"},{"lessThan":"8.12.2","status":"affected","version":"8.0.0","versionType":"semver"},{"status":"unaffected","version":"8.12.2","versionType":"semver"}],"defaultStatus":"unaffected"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:30:04.104974737Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"ranges":[{"type":"SEMVER","events":[{"introduced":"6.5.0"},{"fixed":"6.29.1"}]}],"versions":[]},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:30:04.104974737Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"ranges":[{"type":"SEMVER","events":[{"introduced":"7.0.0"},{"fixed":"7.30.1"}]}],"versions":[]},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:30:04.104974737Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"ranges":[{"type":"SEMVER","events":[{"introduced":"8.0.0"},{"fixed":"8.12.2"}]}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:13:31Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"ecosystem":"npm","name":"undici"},"version":"6.29.1"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:13:31Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"ecosystem":"npm","name":"undici"},"version":"7.30.1"},{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:13:31Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"ecosystem":"npm","name":"undici"},"version":"8.12.2"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-109924","source_modified_at":"2026-10-16T20:05:22.386Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"undici","ecosystem":null},"version":"6.29.1","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-109924","source_modified_at":"2026-10-16T20:05:22.386Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"undici","ecosystem":null},"version":"7.30.1","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-109924","source_modified_at":"2026-10-16T20:05:22.386Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"undici","ecosystem":null},"version":"8.12.2","basis":"first unaffected version stated in the CVE record"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:30:04.104974737Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"version":"6.29.1"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:30:04.104974737Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"version":"7.30.1"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-4qv8-2p9j-2685","source_modified_at":"2026-10-23T22:30:04.104974737Z","fetched_at":"2026-10-24T00:31:04.721601Z","package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"version":"8.12.2"}],"cvss":5.9,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00321,"percentile":0.23844,"score_date":"2026-10-23"},"published_at":"2026-10-15T18:16:48.452Z","modified_at":"2026-10-23T22:30:04.104974737Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-4qv8-2p9j-2685","fetched_at":"2026-10-24T00:31:04.721601Z","source_modified_at":"2026-10-23T22:13:31Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-109924","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-16T20:05:22.386Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-4qv8-2p9j-2685","fetched_at":"2026-10-24T00:31:04.721601Z","source_modified_at":"2026-10-23T22:30:04.104974737Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-109924","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-4qv8-2p9j-2685"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-109924","source":"GitHub Advisory Database"},{"url":"https://github.com/nodejs/undici/commit/299162740d5f39120092277e70efacb4d151c1c6","source":"GitHub Advisory Database"},{"url":"https://github.com/nodejs/undici/commit/789ef26461c648480433846607154f52d74ec9ab","source":"GitHub Advisory Database"},{"url":"https://github.com/nodejs/undici/commit/c43b23fdc6b37e1283d4347408bb16800f867d9e","source":"GitHub Advisory Database"},{"source":"CVE List","url":"https://cna.openjsf.org/security-advisories.html"},{"url":"https://github.com/nodejs/undici/releases/tag/v6.29.1","source":"GitHub Advisory Database"},{"url":"https://github.com/nodejs/undici/releases/tag/v7.30.1","source":"GitHub Advisory Database"},{"url":"https://github.com/nodejs/undici/releases/tag/v8.12.2","source":"GitHub Advisory Database"},{"url":"https://github.com/advisories/GHSA-4qv8-2p9j-2685","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"partial","assessed_at":"2026-10-16T20:05:08.940657Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-23T22:30:04.104974737Z","content_hash":"adb90913423a5d2fd97ec9999a8d8f2a272a3ab4453f80f490d0708fa16d517f"}}