CVE-2026-33750CWE-400

brace-expansion: Zero-step sequence causes process hang and memory exhaustion

Medium · published March 27, 2026

CVSS v3.1
6.5
EPSS
1%
Percentile
48.7
In the wild
Unconfirmed
What it is

The brace-expansion library generates arbitrary strings containing a common prefix and suffix. Prior to versions 5.0.5, 3.0.2, 2.0.3, and 1.1.13, a brace pattern with a zero step value (e.g., `{1..2..0}`) causes the sequence generation loop to run indefinitely, making the process hang for seconds and allocate heaps of memory. Versions 5.0.5, 3.0.2, 2.0.3, and 1.1.13 fix the issue. As a workaround, sanitize strings passed to `expand()` to ensure a step value of `0` is not used.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00613 · 48.7th percentile
Weakness
CWE-400 · Uncontrolled Resource Consumption
Published
2026-03-27T14:04Z
EPSS history
Timeline
  • 27 MAR 14:04Z
    brace-expansion: Zero-step sequence causes process hang and memory exhaustion
    cvelistv5