CVE-2026-10144 in Rsbuild
Summary
by MITRE • 09/15/2026
Rsbuild before 2.0.9 contains a command injection vulnerability that allows attackers to execute arbitrary OS commands by supplying a crafted URL containing shell metacharacters to the server.open configuration on macOS. The openBrowser() function in packages/core/src/server/open.ts passes the URL through encodeURI() before interpolating it into a shell command executed via child_process.exec(), but because encodeURI() does not encode dollar signs, parentheses, or semicolons, embedded shell metacharacters are evaluated by /bin/sh, enabling arbitrary command execution.
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Analysis
by VulDB Data Team • 09/16/2026
The vulnerability identified in Rsbuild versions prior to 2.0.9 represents a critical server-side command injection flaw that arises from improper neutralization of special elements used in operating system commands. This specific weakness is rooted in the implementation of the openBrowser function located within the packages/core/src/server/open.ts module. The core issue stems from an insufficient sanitization strategy where developer input, specifically URLs provided by users or attackers, is processed through a URL encoding mechanism that fails to address all dangerous shell metacharacters. When this flawed data is subsequently interpolated into a system command executed via Node.js child_process.exec(), it allows for the injection and execution of arbitrary operating system commands on the host machine running macOS.
The technical root cause lies in the specific behavior of the encodeURI function used during the preprocessing stage. While encodeURI is designed to escape characters that have special meaning within URIs, such as spaces or non-ASCII characters, it deliberately leaves certain punctuation marks unencoded because they are considered valid components of a URI structure under RFC 3986 standards. These include semicolons, commas, and crucially for this vulnerability, dollar signs, parentheses, and question marks. When the encoded URL string is concatenated into a shell command string like /bin/sh -c open "$url", these unencoded characters retain their syntactic significance within the context of the Bourne shell interpreter. An attacker can craft a malicious URL containing sequences such as $(command) or ; rm -rf /, which will be interpreted by the shell not as literal data but as executable instructions, thereby bypassing any intended isolation between the web application and the underlying operating system.
From an operational perspective, this vulnerability poses severe risks to systems where Rsbuild is deployed with server.open enabled on macOS environments. Successful exploitation allows a remote attacker to achieve arbitrary code execution with the privileges of the user account running the Rsbuild process. This can lead to complete compromise of the development or production environment, including unauthorized access to sensitive files, installation of backdoors, pivoting to other networked systems, and exfiltration of confidential data. The impact is particularly acute in continuous integration or local development scenarios where developers might inadvertently trigger this vulnerability by interacting with crafted links or automated testing tools that supply malformed URLs to the build server.
This flaw aligns directly with Common Weakness Enumeration CWE-78, which classifies improper neutralization of special elements used in an OS command as a distinct category of injection vulnerabilities. Furthermore, it maps to MITRE ATT&CK technique T1059.004, specifically Command and Scripting Interpretation via Unix Shell, highlighting the mechanism by which attackers leverage shell syntax to execute malicious payloads. The vulnerability underscores the critical importance of distinguishing between data intended for display or storage within a URI structure versus data that will be interpreted as executable code by an external process like /bin/sh.
Mitigation strategies must prioritize upgrading to Rsbuild version 2.0.9 or later, where this logic has been corrected to properly sanitize shell metacharacters before command execution. For environments unable to upgrade immediately, a robust workaround involves implementing strict input validation that rejects any URL containing characters such as dollar signs, parentheses, semicolons, ampersands, pipes, and backticks. Alternatively, developers should avoid using child_process.exec for launching external applications when user-supplied data is involved. Instead, they should utilize APIs like open with explicit arguments or employ spawn methods that do not invoke a shell interpreter, thereby eliminating the attack surface associated with command line parsing and metacharacter interpretation.