CVE-2026-14257: brace-expansion DoS via unbounded expansion length causing an out-of-memory process crash

Vulnerability summary

CVE-2026-14257 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in juliangruber brace-expansion. EPSS estimates a 0.64% chance of exploitation in the next 30 days, higher than 50.8% of scored vulnerabilities.

Timeline

1. 23-07-2026
   PublishedVulnerability first disclosed.
2. 23-07-2026
   Last modifiedVulnerability information updated.

Description

brace-expansion through 5.0.7 is vulnerable to denial of service via memory exhaustion. The expand() function limits the number of results with a max option (default 100,000) but does not bound the length of each result string. By chaining multiple brace groups, an attacker keeps the result count under the limit while making each result progressively longer, so total memory scales with both count and string length until the process hits a fatal, uncatchable out-of-memory error. About 7.5 KB of input ('{a,b}'.repeat(1500)) crashes a default Node.js process. Any application that passes attacker-influenced strings to brace-expansion.expand() - directly or transitively via minimatch / glob brace patterns - can be crashed by a small request. Fixed in 5.0.8 by adding a maxLength option (default 4,000,000) that bounds accumulated output and intermediate arrays.

• CWE-400Uncontrolled Resource ConsumptionThe product does not properly control the allocation and maintenance of a limited resource.
• CWE-770Allocation of Resources Without Limits or ThrottlingThe product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.