{"schema":"threatline.record/2","record":{"id":"CVE-2026-107299","aliases":["GHSA-26wq-p25c-j6fv"],"summary":"msgpack5: Reserved byte can cause unbounded stream buffering","details":"### Impact\n\nThe reserved MessagePack byte `0xc1` is incorrectly treated as incomplete input. When it appears at the start of a decoder stream, all subsequent data is retained while the decoder waits for bytes that can never make the value valid, allowing memory exhaustion.\n\n### Patches\n\nThe decoder now rejects `0xc1` as invalid input. Streaming decoders release buffered input and stop after unrecoverable decoding errors.\n\n### Workarounds\n\nReject `0xc1` before streaming input to msgpack5, and enforce stream byte and time limits.","categories":["Libraries & packages"],"product":"msgpack5","vendor":"mcollina","ecosystem":"npm","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-26wq-p25c-j6fv","source_modified_at":"2026-10-08T17:40:02Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"msgpack5"},"range":"< 6.1.0"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-107299","source_modified_at":"2026-10-09T15:15:00.980Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"msgpack5","vendor":"mcollina","versions":[{"version":"< 6.1.0","status":"affected"}],"defaultStatus":null},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-26wq-p25c-j6fv","source_modified_at":"2026-10-08T18:00:08.901031374Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"msgpack5","ecosystem":"npm","purl":"pkg:npm/msgpack5"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"6.1.0"}]}],"versions":[]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-26wq-p25c-j6fv","source_modified_at":"2026-10-08T17:40:02Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"npm","name":"msgpack5"},"version":"6.1.0"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-26wq-p25c-j6fv","source_modified_at":"2026-10-08T18:00:08.901031374Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"msgpack5","ecosystem":"npm","purl":"pkg:npm/msgpack5"},"version":"6.1.0"}],"cvss":5.9,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00389,"percentile":0.31797,"score_date":"2026-10-23"},"published_at":"2026-10-08T17:09:47.191Z","modified_at":"2026-10-09T15:15:00.980Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-26wq-p25c-j6fv","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-08T17:40:02Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-107299","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-09T15:15:00.980Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-26wq-p25c-j6fv","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-08T18:00:08.901031374Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-107299","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/mcollina/msgpack5/security/advisories/GHSA-26wq-p25c-j6fv","tags":["x_refsource_CONFIRM"]},{"source":"CVE List","url":"https://github.com/mcollina/msgpack5/commit/85da345bf1acc18ca441741e5cf4aa0ed0d69314","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/mcollina/msgpack5/releases/tag/v6.1.0","tags":["x_refsource_MISC"]},{"url":"https://github.com/advisories/GHSA-26wq-p25c-j6fv","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":"2026-10-08T20:23:17.872522Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-09T15:15:00.980Z","content_hash":"8e73226e087215156e29bed9ed7747f41b3ad9b4e91e3de3bbf1f842cfb81398"}}