Prototype pollution via unsafe deep merge
Published Jul 18, 2026 · Updated Jul 18, 2026
Prototype pollution in Robin Herbots Inputmask 5.0.0 through 5.0.9 allows remote authenticated users to alter inherited object properties. The shared extend helper reads and writes dynamic source keys without rejecting proto, causing nested data supplied to extendDefaults, extendDefinitions, or extendAliases to be merged into Object.prototype. Exploitation requires a consuming application to pass untrusted configuration into these APIs; resulting logic errors, service interruption, or security bypasses depend on later inherited-property use.
Summary
What happened
Prototype pollution in Robin Herbots Inputmask 5.0.0 through 5.0.9 allows remote authenticated users to alter inherited object properties. The shared extend helper reads and writes dynamic source keys without rejecting proto, causing nested data supplied to extendDefaults, extendDefinitions, or extendAliases to be merged into Object.prototype. Exploitation requires a consuming application to pass untrusted configuration into these APIs; resulting logic errors, service interruption, or security bypasses depend on later inherited-property use.
The record
- CVE
- CVE-2026-16150
- Published
- Jul 18, 2026
- Updated
- Jul 18, 2026
- Vendor
- Robin Herbots
- Product
- Inputmask
- Classifications
- CWE-94, CWE-1321
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 18, 2026CVE publishedPublication date reported by the CVE source.
- Jul 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.0.0
- Affected versionversion=5.0.1
- Affected versionversion=5.0.2
- Affected versionversion=5.0.3
- Affected versionversion=5.0.4
- Affected versionversion=5.0.5
- Affected versionversion=5.0.6
- Affected versionversion=5.0.7
- Affected versionversion=5.0.8
- Affected versionversion=5.0.9
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Prototype pollution in extendDefaults() via unsafe deep mergeproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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