Resource exhaustion in Juliangruber Brace-Expansion

CVE-2026-102277

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.

Vulnerability class: DoS (Denial of Service)

Published .

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-102277?
CVE-2026-102277 is a medium-severity vulnerability in Juliangruber Brace-Expansion, classified under Uncontrolled Resource Consumption. CVSS score: 5.3/10. Published 2026-09-28.
How severe is CVE-2026-102277?
Medium severity. CVSS v3 base score is 5.3 out of 10.