{"id":"UBUNTU-CVE-2026-93753","details":"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.","modified":"2026-09-21T21:40:59.256708273Z","published":"2026-09-21T00:00:00Z","upstream":["CVE-2026-93753"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-93753"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-93753"},{"type":"REPORT","url":"https://github.com/TehShrike/deepmerge/issues/273"},{"type":"REPORT","url":"https://github.com/TehShrike/deepmerge"},{"type":"REPORT","url":"https://github.com/TehShrike/deepmerge/blob/5b87756a5671635679001cbac72aa42f23472c81/index.js#L39-L60"},{"type":"REPORT","url":"https://www.vulncheck.com/advisories/deepmerge-through-4.3.1-prototype-poisoning-via-mergeobject"}],"affected":[{"package":{"name":"node-deepmerge","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/node-deepmerge?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.2.2-3","4.2.2+~1.1.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"node-deepmerge","binary_version":"4.2.2+~1.1.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93753.json"}},{"package":{"name":"node-deepmerge","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/node-deepmerge?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.2.2+~1.1.1-3","4.3.1+~1.1.1-1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"4.3.1+~1.1.1-1build1","binary_name":"node-deepmerge"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93753.json"}},{"package":{"name":"node-deepmerge","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/node-deepmerge?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.3.1+~1.1.1-1build1"],"ecosystem_specific":{"binaries":[{"binary_version":"4.3.1+~1.1.1-1build1","binary_name":"node-deepmerge"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93753.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"},{"type":"Ubuntu","score":"medium"}]}