CVE-2026-93753

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.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/TehShrike/deepmerge
https://github.com/TehShrike/deepmerge/blob/5b87756a5671635679001cbac72aa42f23472c81/index.js#L39-L60
https://github.com/TehShrike/deepmerge/issues/273
https://www.vulncheck.com/advisories/deepmerge-through-4.3.1-prototype-poisoning-via-mergeobject
https://github.com/TehShrike/deepmerge/issues/273

Configurations

No configuration.

History

18 Sep 2026, 20:17

Type	Values Removed	Values Added
References	~~() https://github.com/TehShrike/deepmerge/issues/273 -~~	() https://github.com/TehShrike/deepmerge/issues/273 -

18 Sep 2026, 18:18

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-18 18:18

Updated : 2026-09-23 17:17

NVD link : CVE-2026-93753

Mitre link : CVE-2026-93753

CVE.ORG link : CVE-2026-93753

JSON object : View

Products Affected

No product.

CWE

CWE-1321

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

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