Skip to content

brace-expansion: Large numeric range defeats documented `max` DoS protection

Moderate severity GitHub Reviewed Published May 12, 2026 in juliangruber/brace-expansion • Updated May 18, 2026

Package

npm brace-expansion (npm)

Affected versions

>= 5.0.0, < 5.0.6

Patched versions

5.0.6

Description

The max option was being applied too late:

When expanding a single large numeric range like {1..10000000}, the sequence generation loop generates all 10 million intermediate elements before the max limit is applied With max=10, the output is correctly limited to 10 items, but the process still allocates ~505 MB and spends ~800ms building the full intermediate array.

Workaround

Ensure the string to be expanded doesn't contain more values than the desired max item count.

References

@juliangruber juliangruber published to juliangruber/brace-expansion May 12, 2026
Published to the GitHub Advisory Database May 18, 2026
Reviewed May 18, 2026
Last updated May 18, 2026

Severity

Moderate

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS score

Weaknesses

Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource. Learn more on MITRE.

CVE ID

CVE-2026-45149

GHSA ID

GHSA-jxxr-4gwj-5jf2

Source code

Credits

Loading Checking history
See something to contribute? Suggest improvements for this vulnerability.