CVE-2026-102278: brace-expansion: DoS via uncontrolled recursion on nested brace groups causing stack exhaustion

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-28 · updated 2026-10-01
Weakness: CWE-400

Description

The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to 1.1.20, 2.1.6, 3.0.8, and 5.0.11, deeply nested brace groups cause expand_() to recurse once per nesting level at comma-member and single-set expansion sites, exhausting the native stack before output limits can apply and potentially terminating the Node.js process. expand_ performs uncontrolled recursion for nested brace alternatives and single-part sets. deeply nested brace groups supplied as an untrusted pattern. expand_ is affected. expand is affected. Comma members is affected. Single set is affected. native stack exhaustion during nested sub-expansion. process-terminating denial of service. This issue is fixed in versions 1.1.20, 2.1.6, 3.0.8, and 5.0.11.

Affected products

Npm Brace-Expansion: from 4.0.0 before 5.0.11; from 3.0.0 before 3.0.8; from 2.0.0 before 2.1.6; before 1.1.20 — fixed in 5.0.11, 3.0.8, 2.1.6, 1.1.20
juliangruber brace-expansion: from 4.0.0, < 5.0.11; from 3.0.0, < 3.0.8; from 2.0.0, < 2.1.6; before 1.1.20

How to fix

Upgrade to a fixed version: Npm Brace-Expansion 5.0.11, 3.0.8, 2.1.6, 1.1.20. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-102278 or the next vulnerability affects your stack