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CVE-2026-27601 Detail

Description

Underscore.js is a utility-belt library for JavaScript. Prior to 1.13.8, the _.flatten and _.isEqual functions use recursion without a depth limit. Under very specific conditions, detailed below, an attacker could exploit this in a Denial of Service (DoS) attack by triggering a stack overflow. Untrusted input must be used to create a recursive datastructure, for example using JSON.parse, with no enforced depth limit. The datastructure thus created must be passed to _.flatten or _.isEqual. In the case of _.flatten, the vulnerability can only be exploited if it is possible for a remote client to prepare a datastructure that consists of arrays at all levels AND if no finite depth limit is passed as the second argument to _.flatten. In the case of _.isEqual, the vulnerability can only be exploited if there exists a code path in which two distinct datastructures that were submitted by the same remote client are compared using _.isEqual. For example, if a client submits data that are stored in a database, and the same client can later submit another datastructure that is then compared to the data that were saved in the database previously, OR if a client submits a single request, but its data are parsed twice, creating two non-identical but equivalent datastructures that are then compared. Exceptions originating from the call to _.flatten or _.isEqual, as a result of a stack overflow, are not being caught. This vulnerability is fixed in 1.13.8.


Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  GitHub, Inc.
CVSS-B 8.2 HIGH
Vector:  CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/jashkenas/underscore/commit/411e222eb0ca5d570cc4f6315c02c05b830ed2b4 GitHub, Inc.
https://github.com/jashkenas/underscore/commit/a6e23ae9647461ec33ad9f92a2ecfc220eea0a84 GitHub, Inc.
https://github.com/jashkenas/underscore/security/advisories/GHSA-qpx9-hpmf-5gmw GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-770 Allocation of Resources Without Limits or Throttling GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-27601
NVD Published Date:
03/03/2026
NVD Last Modified:
03/03/2026
Source:
GitHub, Inc.