Mongoose, a MongoDB object modeling tool, had a vulnerability (CVE-2026-42334) where its sanitizeFilter mechanism failed to sanitize the $nor logical operator. While sanitizeFilter wraps query operators in $eq to neutralize them, $nor was omitted from recursive sanitization. Since $nor accepts arrays and arrays do not trigger the hasDollarKeys() check, attackers could inject operators like $ne, $gt, or $regex inside $nor clauses, bypassing sanitization. This flaw was addressed in mongoose versions 6.13.9, 7.8.9, 8.22.1, and 9.1.6.

The vulnerability allows an attacker to bypass mongoose's query sanitization, potentially enabling injection of malicious query operators that could lead to unauthorized data disclosure. The CVSS score of 7.5 indicates a high severity impact on confidentiality. There is no indication of impact on integrity or availability. No known exploits are reported in the wild at this time.

A fix is available in mongoose versions 6.13.9, 7.8.9, 8.22.1, and 9.1.6. Users should upgrade to these or later versions to remediate the vulnerability. Patch status is not explicitly stated in a vendor advisory, but the fixed versions are clearly identified. No additional mitigation steps are specified.