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.
- Published Sep 18, 2026
- CVSS 8.7 high
- 0.5% chance of exploitation in the next 30 days (EPSS)