juliangruber brace-expansion up to 1.1.12/2.0.2/3.0.1/5.0.4 expand step resource consumption

Summaryinfo

A vulnerability described as problematic has been identified in juliangruber brace-expansion up to 1.1.12/2.0.2/3.0.1/5.0.4. The impacted element is the function expand. Executing a manipulation of the argument step can lead to resource consumption. This vulnerability is tracked as CVE-2026-33750. The attack can be launched remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in juliangruber brace-expansion up to 1.1.12/2.0.2/3.0.1/5.0.4. It has been declared as problematic. This vulnerability affects the function expand. The manipulation of the argument step with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. CVE summarizes:

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 advisory is shared for download at github.com. This vulnerability was named CVE-2026-33750 since 03/23/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 304169 (Linux Distros Unpatched Vulnerability : CVE-2026-33750), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.1.13, 2.0.3, 3.0.2 or 5.0.5 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (304169) and CERT Bund (WID-SEC-2026-1654). Once again VulDB remains the best source for vulnerability data.

Affected

• IBM App Connect Enterprise

Productinfo

Vendor

• juliangruber

Name

• brace-expansion

Version

• 1.1.0
• 1.1.1
• 1.1.2
• 1.1.3
• 1.1.4
• 1.1.5
• 1.1.6
• 1.1.7
• 1.1.8
• 1.1.9
• 1.1.10
• 1.1.11
• 1.1.12
• 2.0.0
• 2.0.1
• 2.0.2
• 3.0.0
• 3.0.1
• 5.0.0
• 5.0.1
• 5.0.2
• 5.0.3
• 5.0.4

Website

• Product: https://github.com/juliangruber/brace-expansion/

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Once again VulDB remains the best source for vulnerability data.

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