CVE-2026-93687 in braces
Summary
by MITRE • 09/18/2026
braces through 3.0.3 contains a stack overflow vulnerability in the recursive AST walkers that lack depth guards. Attackers can supply deeply nested brace patterns under the character limit to exhaust the call stack and terminate the Node.js process with an uncaught RangeError.
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Analysis
by VulDB Data Team • 09/18/2026
The braces library, specifically through version 3.0.3, contains a critical stack overflow vulnerability within its recursive Abstract Syntax Tree (AST) walkers. This flaw arises from the absence of depth guards in the parsing logic that processes brace expansion patterns. When the library encounters input containing deeply nested brace structures, it recursively invokes internal functions to parse and expand these patterns without tracking or limiting the recursion depth. Consequently, an attacker can craft a maliciously constructed string with excessive nesting levels that remains within standard character limits but triggers unbounded recursive calls. This behavior leads to rapid exhaustion of the JavaScript call stack in Node.js environments, resulting in an uncaught RangeError that abruptly terminates the application process.
From a technical perspective, this vulnerability is classified under CWE-675, which denotes operations with duplicate or unnecessary steps, specifically manifesting here as insufficient depth checking during recursive processing. The lack of a maximum recursion limit allows the call stack to grow until it exceeds the memory allocation provided by the runtime environment. In Node.js applications that utilize braces for template expansion, glob matching, or path generation, this vulnerability can be exploited remotely if user-supplied input is passed directly into brace expansion functions without sanitization. The impact includes a denial of service condition where the affected process crashes unexpectedly, potentially disrupting availability and requiring manual intervention to restart services.
This issue aligns with ATT&CK technique T1499, Endpoint Denial of Service, as it enables an attacker to disrupt system functionality by exhausting computational resources through malformed input. The vulnerability highlights a common pitfall in recursive algorithm design where assumptions about input complexity are not enforced via explicit constraints. To mitigate this risk, developers should upgrade the braces library to version 3.0.4 or later, which implements proper depth guards and limits recursion to prevent stack exhaustion. Additionally, implementing input validation that restricts nesting levels before passing data to parsing functions can provide an additional layer of defense against such recursive exploitation attempts in legacy systems where immediate upgrades are not feasible.