{"id":"CVE-2026-106448","state":"PUBLISHED","title":"StableLib: Prototype poisoning via `__proto__` map keys in CBOR decoding","description":"StableLib is a stable library of useful TypeScript and JavaScript code. Prior to 2.0.4, the @stablelib/cbor CBOR map decoding path creates ordinary JavaScript objects and assigns attacker-controlled keys with bracket assignment. A map key named __proto__ invokes the inherited prototype setter instead of creating an ordinary own property, allowing the decoded object's prototype to contain attacker-controlled authorization or feature-flag values. Downstream code that trusts normal property lookup or merges the decoded object can therefore make security-sensitive decisions using inherited attacker data. This issue is fixed in version 2.0.4.","publishedAt":"2026-10-06T19:45:02.616Z","updatedAt":"2026-10-07T17:07:38.703Z","severity":{"score":8.9,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["StableLib stablelib"],"affected":[{"vendor":"StableLib","product":"stablelib","versions":[{"version":"< 2.0.4","status":"affected"}]}],"references":["https://github.com/StableLib/stablelib/security/advisories/GHSA-w48f-fwg7-ww6p","https://github.com/StableLib/stablelib/commit/0f153a63b7552a0e8721f640984113e419015026","https://github.com/StableLib/stablelib/releases/tag/@stablelib/cbor@2.0.4"],"weaknesses":["CWE-1321"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/106xxx/CVE-2026-106448.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-106448","state":"PUBLISHED","datePublished":"2026-10-06T19:45:02.616Z","dateUpdated":"2026-10-07T17:07:38.703Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-10-06T16:49:40.590Z"},"containers":{"cna":{"title":"StableLib: Prototype poisoning via `__proto__` map keys in CBOR decoding","descriptions":[{"lang":"en","value":"StableLib is a stable library of useful TypeScript and JavaScript code. Prior to 2.0.4, the @stablelib/cbor CBOR map decoding path creates ordinary JavaScript objects and assigns attacker-controlled keys with bracket assignment. A map key named __proto__ invokes the inherited prototype setter instead of creating an ordinary own property, allowing the decoded object's prototype to contain attacker-controlled authorization or feature-flag values. Downstream code that trusts normal property lookup or merges the decoded object can therefore make security-sensitive decisions using inherited attacker data. This issue is fixed in version 2.0.4."}],"affected":[{"vendor":"StableLib","product":"stablelib","versions":[{"version":"< 2.0.4","status":"affected"}]}],"references":[{"url":"https://github.com/StableLib/stablelib/security/advisories/GHSA-w48f-fwg7-ww6p","name":"https://github.com/StableLib/stablelib/security/advisories/GHSA-w48f-fwg7-ww6p","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/StableLib/stablelib/commit/0f153a63b7552a0e8721f640984113e419015026","name":"https://github.com/StableLib/stablelib/commit/0f153a63b7552a0e8721f640984113e419015026","tags":["x_refsource_MISC"]},{"url":"https://github.com/StableLib/stablelib/releases/tag/@stablelib/cbor@2.0.4","name":"https://github.com/StableLib/stablelib/releases/tag/@stablelib/cbor@2.0.4","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"HIGH","subAvailabilityImpact":"NONE","baseScore":8.9,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-1321","lang":"en","description":"CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-06T19:45:02.616Z"},"source":{"advisory":"GHSA-w48f-fwg7-ww6p","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-07T15:27:16.755969Z","id":"CVE-2026-106448","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-07T17:07:38.703Z"}}]}}}