CVE-2024-24576 in Rust
Summary
by MITRE • 04/09/2024
Rust is a programming language. The Rust Security Response WG was notified that the Rust standard library prior to version 1.77.2 did not properly escape arguments when invoking batch files (with the `bat` and `cmd` extensions) on Windows using the `Command`. An attacker able to control the arguments passed to the spawned process could execute arbitrary shell commands by bypassing the escaping. The severity of this vulnerability is critical for those who invoke batch files on Windows with untrusted arguments. No other platform or use is affected.
The `Command::arg` and `Command::args` APIs state in their documentation that the arguments will be passed to the spawned process as-is, regardless of the content of the arguments, and will not be evaluated by a shell. This means it should be safe to pass untrusted input as an argument.
On Windows, the implementation of this is more complex than other platforms, because the Windows API only provides a single string containing all the arguments to the spawned process, and it's up to the spawned process to split them. Most programs use the standard C run-time argv, which in practice results in a mostly consistent way arguments are splitted.
One exception though is `cmd.exe` (used among other things to execute batch files), which has its own argument splitting logic. That forces the standard library to implement custom escaping for arguments passed to batch files. Unfortunately it was reported that our escaping logic was not thorough enough, and it was possible to pass malicious arguments that would result in arbitrary shell execution.
Due to the complexity of `cmd.exe`, we didn't identify a solution that would correctly escape arguments in all cases. To maintain our API guarantees, we improved the robustness of the escaping code, and changed the `Command` API to return an `InvalidInput` error when it cannot safely escape an argument. This error will be emitted when spawning the process.
The fix is included in Rust 1.77.2. Note that the new escaping logic for batch files errs on the conservative side, and could reject valid arguments. Those who implement the escaping themselves or only handle trusted inputs on Windows can also use the `CommandExt::raw_arg` method to bypass the standard library's escaping logic.
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Analysis
by VulDB Data Team • 04/16/2026
The vulnerability CVE-2024-24576 represents a critical security flaw in the Rust standard library's handling of command execution on Windows platforms. This issue affects versions prior to Rust 1.77.2 and specifically targets the interaction between Rust's Command API and Windows batch file execution mechanisms. The vulnerability arises from insufficient argument escaping when invoking batch files with .bat and .cmd extensions, creating a potential for arbitrary command execution through specially crafted input parameters. The security implications are severe because the standard library's documentation explicitly states that arguments passed through Command::arg and Command::args APIs should be treated as-is without shell evaluation, making developers believe that untrusted input can be safely passed without additional sanitization.
The technical root cause stems from the fundamental differences between Windows and Unix-like operating systems in how command arguments are processed. While Unix systems typically use execve() with separate argument arrays, Windows requires a single string containing all arguments that must be parsed by the target process. The Windows command processor cmd.exe implements its own argument splitting logic that differs from standard C runtime argv parsing, creating a complex edge case in the Rust standard library's implementation. This discrepancy forced the standard library to implement custom escaping mechanisms for Windows batch file execution, but the initial implementation failed to properly handle all edge cases in argument parsing, allowing attackers to craft malicious arguments that would bypass the escaping mechanism and execute unintended shell commands.
The operational impact of this vulnerability extends beyond simple command injection, as it fundamentally undermines the security assumptions developers make when using Rust's Command API on Windows systems. Attackers who can control command arguments passed to batch files can leverage this vulnerability to execute arbitrary shell commands with the privileges of the executing process, potentially leading to complete system compromise. The vulnerability affects any application that spawns batch files on Windows with untrusted input, making it particularly dangerous in server applications, build systems, or any software that processes user-provided data through command execution. Security researchers categorize this under CWE-78 as a "Improper Neutralization of Special Elements used in an OS Command" and aligns with ATT&CK technique T1059.003 for Command and Scripting Interpreter: Windows Command Shell, demonstrating how improper argument handling can enable privilege escalation and lateral movement within compromised systems.
The fix implemented in Rust 1.77.2 addresses this by introducing more conservative escaping logic that prioritizes safety over compatibility, returning InvalidInput errors when the standard library cannot safely escape arguments. This approach ensures that the API guarantees remain intact while preventing potential exploitation. The solution maintains the API contract that arguments are passed as-is but adds a safety check that prevents execution of potentially malicious inputs. Developers who require more control over argument handling can utilize the CommandExt::raw_arg method to bypass the standard library's escaping logic entirely, though this requires careful implementation to avoid reintroducing similar vulnerabilities. The updated implementation reflects a shift toward defensive programming practices in system-level APIs, ensuring that security considerations take precedence over convenience when dealing with platform-specific complexities. Organizations should immediately upgrade to Rust 1.77.2 or later versions to mitigate this critical vulnerability, particularly those running applications that process untrusted input through Windows batch file execution paths.