tehshrike/deepmerge · Security
deepmerge mergeObject() allows prototype poisoning of returned objects
- GHSA ID
- GHSA-gcqx-w48m-w2h4
- CVE ID
- CVE-2026-93753
- Severity
- low
- Published
- Updated
- CVSS
- 5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CVSS v3
- 5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CVSS v4
- 2.7 · 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
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.
CWEs
- CWE-1321 · Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-93753 ↗
- https://github.com/TehShrike/deepmerge/issues/273 ↗
- 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 ↗
- https://github.com/advisories/GHSA-gcqx-w48m-w2h4 ↗