{"id":"CVE-2026-93753","published":"2026-09-18T18:18:34.487","lastModified":"2026-09-23T17:17:50.017","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.","cvssScore":7.5,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","cwes":["CWE-1321"],"vendors":[],"products":[],"references":[{"url":"https://github.com/TehShrike/deepmerge","tags":[]},{"url":"https://github.com/TehShrike/deepmerge/blob/5b87756a5671635679001cbac72aa42f23472c81/index.js#L39-L60","tags":[]},{"url":"https://github.com/TehShrike/deepmerge/issues/273","tags":[]},{"url":"https://www.vulncheck.com/advisories/deepmerge-through-4.3.1-prototype-poisoning-via-mergeobject","tags":[]},{"url":"https://github.com/TehShrike/deepmerge/issues/273","tags":[]}],"exploitRefs":[{"url":"https://github.com/TehShrike/deepmerge","tags":[]},{"url":"https://github.com/TehShrike/deepmerge/blob/5b87756a5671635679001cbac72aa42f23472c81/index.js#L39-L60","tags":[]},{"url":"https://github.com/TehShrike/deepmerge/issues/273","tags":[]},{"url":"https://github.com/TehShrike/deepmerge/issues/273","tags":[]}],"hasPoc":true,"ai":null}