High severity · published Mar 27, 2026
CVE-2026-33750
brace-expansion: Zero-step sequence causes process hang and memory exhaustion
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BR
brace-expansion · juliangruber
>= 4.0.0, < 5.0.5; >= 3.0.0, < 3.0.2; >= 2.0.0, < 2.0.3; < 1.1.13 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-33750
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-33750
Patch
https://github.com/juliangruber/brace-expansion/blob/daa71bcb4a30a2df9bcb7f7b8daaf2ab30e5794a/src/index.ts#L107-L113
Patch
https://github.com/juliangruber/brace-expansion/blob/daa71bcb4a30a2df9bcb7f7b8daaf2ab30e5794a/src/index.ts#L184
Patch
https://github.com/juliangruber/brace-expansion/commit/311ac0d54994158c0a384e286a7d6cbb17ee8ed5
Patch
https://github.com/juliangruber/brace-expansion/commit/7fd684f89fdde3549563d0a6522226a9189472a2
Patch
https://github.com/juliangruber/brace-expansion/commit/b9cacd9e55e7a1fa588fe4b7bb1159d52f1d902a
Issue Tracking
https://github.com/juliangruber/brace-expansion/issues/98
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