maker.js: Improperly Controlled Modification of Object Prototype Attributes
CVE-2026-24888 is a critical-severity improperly controlled modification of object prototype attributes vulnerability in maker.js from Microsoft, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected maker.js versions: <= 0.19.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1% chance of exploitation within 30 days, higher than 63% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of maker.js you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 6.5 | Medium | CNA (github.com) |
| CVSS 3.1 | 9.8 | Critical | NVD |
Official description
Maker.js is a 2D vector line drawing and shape modeling for CNC and laser cutters. In versions up to and including 0.19.1, the `makerjs.extendObject` function copies properties from source objects without proper validation, potentially exposing applications to security risks. The function lacks `hasOwnProperty()` checks and does not filter dangerous keys, allowing inherited properties and potentially malicious properties to be copied to target objects. A patch is available in commit 85e0f12bd868974b891601a141974f929dec36b8, which is expected to be part of version 0.19.2.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improperly Controlled Modification of Object Prototype Attributes
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
How developers prevent this class of flaw
- By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
- By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
- When handling untrusted objects, validating using a schema can be used.
More Improperly Controlled Modification of Object Prototype Attributes vulnerabilities (CWE-1321)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Improperly Controlled Modification of Object Prototype Attributes vulnerabilities
- 9.8 Critical severity
- 9.3 Critical severity
- 8.5 High severity
- 8.6 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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