CVE-2026-42334 — mongoose
HIGHCVE-2026-42334 is a high-severity (CVSS 7.5) CWE-74 vulnerability in mongoose. A fix is available for mongoose — see the affected versions and patch details below.
Mongoose: Improper Sanitization of $nor in sanitizeFilter May Allow NoSQL Injection
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-42334.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
mongoosenpmDescription
Impact
This vulnerability allows bypassing Mongoose’s sanitizeFilter query sanitization mechanism via the $nor operator.
When sanitizeFilter is enabled, Mongoose wraps query operators in $eq to neutralize them. However, prior to the fix, $nor was not included in the set of logical operators that are recursively sanitized. Because $nor accepts an array (like $and and $or), and arrays do not trigger hasDollarKeys(), malicious operators such as $ne, $gt, or $regex could be injected inside a $nor clause without being sanitized.
This may lead to:
- Authentication bypass
- Unauthorized data access
- Data exfiltration
Affected users:
Applications that:
- Explicitly enable sanitizeFilter
- Pass unsanitized user-controlled input directly into query methods (e.g.,
Model.findOne(req.body)) and rely onsanitizeFilterto strip out query selectors
Applications that validate input schemas, whitelist fields, or avoid passing raw request bodies into queries are not affected. For example, Model.findOne({ user: req.body.user, pwd: req.body.pwd }) is not affected.
Patches
Patches have been released for all supported Mongoose release lines:
^6.13.9^7.8.9^8.22.1^9.1.6
Workarounds
Delete $nor keys, use an additional schema validation library, or write middleware to strip out $nor from query filters.
Resources
sanitizeFilter documentation: https://mongoosejs.com/docs/api/mongoose.html#Mongoose.prototype.sanitizeFilter()
Original blog post on sanitizeFilter: https://thecodebarbarian.com/whats-new-in-mongoose-6-sanitizefilter.html
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | mongoose | all versions | 6.13.9npm install mongoose@6.13.9 |
| 📦npm | mongoose | ≥ 7.0.0&&< 7.8.9 | 7.8.9npm install mongoose@7.8.9 |
| 📦npm | mongoose | ≥ 8.0.0&&< 8.22.1 | 8.22.1npm install mongoose@8.22.1 |
| 📦npm | mongoose | ≥ 9.0.0&&< 9.1.6 | 9.1.6npm install mongoose@9.1.6 |
Affected Products
mongoosemongoosejsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mongoose, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mongoose to 6.13.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42334 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2026-42334 in your dependencies?
Find it across npm, including transitive dependencies.