CVE-2026-102277: juliangruber brace-expansion Uncontrolled Resource Consumption

Vulnerability summary

CVE-2026-102277 is a medium (CVSS 5.3) Uncontrolled Resource Consumption vulnerability in juliangruber brace-expansion. EPSS estimates a 0.30% chance of exploitation in the next 30 days, higher than 21.5% of scored vulnerabilities.

Timeline

1. 28-09-2026
   PublishedVulnerability first disclosed.
2. 29-09-2026
   Last modifiedVulnerability information updated.

Description

The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to 1.1.21, 2.1.7, 3.0.9, and 5.0.12, the expand function handles untrusted {a},b}-shaped patterns with many trailing closing braces by restarting its scan once for each trailing closing brace. The successive full-input rescans with linear working-string growth cause quadratic CPU time and memory pressure that can block the Node.js event loop. The process eventually recovers, making the impact a recoverable CPU denial of service. This issue is fixed in versions 1.1.21, 2.1.7, 3.0.9, and 5.0.12.

• CWE-400Uncontrolled Resource ConsumptionThe product does not properly control the allocation and maintenance of a limited resource.
• CWE-407Inefficient Algorithmic ComplexityAn algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.