Prototype Pollution in Tehshrike Deepmerge
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.
Vulnerability class: Prototype Pollution
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
Affected products
Weakness classification (CWE)
References
- disclosure@vulncheck.com (issue-tracking)
- disclosure@vulncheck.com (product)
- disclosure@vulncheck.com (technical-description)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-93753?
- CVE-2026-93753 is a high-severity vulnerability in Tehshrike Deepmerge, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 7.5/10. Published 2026-09-18.
- How severe is CVE-2026-93753?
- High severity. CVSS v3 base score is 7.5 out of 10.