Quick answers
- Is This vulnerability exploited in the wild?
- No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
- How severe is This vulnerability?
- Informational severity, published 3 September 2020.
- Which products and versions are affected?
- lodash.mergewith (npm) before 4.6.1.
- Is there a fix for This vulnerability?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is This vulnerability attacked?
- It is attacked over the network, in a software library.
- Am I affected?
- Check whether you run lodash.mergewith (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
This is a prototype pollution vulnerability (CWE-1321) in the mergeWith function that fails to properly sanitize the __proto__ property during object merge operations. An attacker can supply a crafted object containing __proto__ as a key, which causes the function to modify the Object prototype itself rather than a regular property. This affects all objects in the application, potentially leading to property injection, authentication bypass, or code execution depending on how the application uses object properties. The vulnerability exists in all versions prior to 4.6.1, which fixed the issue. No authentication or user interaction is required; an attacker simply needs to control input passed to mergeWith.
Affected products
- npm lodash.mergewith before 4.6.1
Timeline
- 2020-09-03: disclosed