{"id":"GHSA-gcqx-w48m-w2h4","revision":"2f674d3460e44880bbcf6e5facc06178","records":[{"revision":"2f674d3460e44880bbcf6e5facc06178","observedAt":"2026-10-27T22:46:24.417+00:00","statement":{"source":"osv","id":"GHSA-gcqx-w48m-w2h4","aliases":["CVE-2026-93753"],"title":"deepmerge mergeObject() allows prototype poisoning of returned objects","description":"deepmerge through 4.3.1 contains a prototype poisoning vulnerability in the mergeObject() function that fails to properly validate keys being written to target objects. Attackers can supply malicious source objects in merge operations to inject attacker-controlled properties into the returned object's prototype, causing applications to inherit unintended values when accessing properties without own-property checks.","state":0,"publishedAt":"2026-09-18T18:31:44+00:00","modifiedAt":"2026-10-27T21:45:04.256048+00:00","affected":[{"ecosystem":"npm","name":"deepmerge","ranges":[{"type":"SEMVER","events":[{"kind":"introduced","version":"4.2.0"},{"kind":"last_affected","version":"4.3.1"}]}],"versions":[],"rawVersionEvidence":null}],"metrics":[{"system":"CVSS_V3","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":null,"severity":null},{"system":"CVSS_V4","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U","score":null,"severity":null},{"system":"Publisher rating","vector":null,"score":null,"severity":"LOW"}],"references":["https://nvd.nist.gov/vuln/detail/CVE-2026-93753","https://github.com/TehShrike/deepmerge/issues/273","https://github.com/TehShrike/deepmerge","https://github.com/TehShrike/deepmerge/blob/5b87756a5671635679001cbac72aa42f23472c81/index.js#L39-L60","https://www.vulncheck.com/advisories/deepmerge-through-4.3.1-prototype-poisoning-via-mergeobject"],"sourceUrl":"https://github.com/advisories/GHSA-gcqx-w48m-w2h4","license":"GitHub Advisory Database · CC-BY-4.0","key":"osv:GHSA-gcqx-w48m-w2h4","identifiers":["GHSA-gcqx-w48m-w2h4","CVE-2026-93753"]},"retained":false,"historicalAffected":[]}],"coverage":[]}