CliInvoke.Specializations: Command injection in PowerShell and Cmd shell wrappers

CliInvoke is a .NET library for invoking command-line programs, and its `CliInvoke.Specializations` packages provide specialized wrappers for shells such as PowerShell and Windows Command Prompt. `CliInvoke.Specializations` versions 2.2.0 through 2.8.4, 2.9.0 through 2.9.3, 2.10.0 through 2.10.4, 3.0.0-alpha.1 through 3.0.0-alpha.4, and 3.0.0-alpha.8 through 3.0.0-alpha.10, as well as `AlastairLundy.CliInvoke.Specializations` versions 1.0.0-rc.1 through 1.6.1.1, contain an OS command injection vulnerability in their PowerShell and Cmd wrappers. The wrappers pass a caller-controlled target and arguments to `pwsh -Command` or `cmd /c` using a single `ProcessStartInfo.Arguments` string, allowing a double quote in untrusted input to break operating-system-level quoting and cause the shell to execute an additional command with the host process's privileges. The vulnerability is patched in `CliInvoke.Specializations` versions 2.8.5, 2.9.4, 2.10.5, and 3.0.0-beta.1, and in `AlastairLundy.CliInvoke.Specializations` version 2.0.2. No complete workaround is available; users unable to upgrade should reject or remove double quotes from target paths and arguments, additionally reject shell metacharacters in versions 2.2.0 through 2.9.2 and 3.0.0-alpha.1 through 3.0.0-alpha.4, or bypass the PowerShell and Cmd wrappers and invoke target processes directly when handling untrusted input.

CliInvoke is a .NET library for invoking command-line programs, and its `CliInvoke.Specializations` packages provide specialized wrappers for shells such as PowerShell and Windows Command Prompt. `CliInvoke.Specializations` versions 2.2.0 through 2.8.4, 2.9.0 through 2.9.3, 2.10.0 through 2.10.4, 3.0.0-alpha.1 through 3.0.0-alpha.4, and 3.0.0-alpha.8 through 3.0.0-alpha.10, as well as `AlastairLundy.CliInvoke.Specializations` versions 1.0.0-rc.1 through 1.6.1.1, contain an OS command injection vulnerability in their PowerShell and Cmd wrappers. The wrappers pass a caller-controlled target and arguments to `pwsh -Command` or `cmd /c` using a single `ProcessStartInfo.Arguments` string, allowing a double quote in untrusted input to break operating-system-level quoting and cause the shell to execute an additional command with the host process's privileges. The vulnerability is patched in `CliInvoke.Specializations` versions 2.8.5, 2.9.4, 2.10.5, and 3.0.0-beta.1, and in `AlastairLundy.CliInvoke.Specializations` version 2.0.2. No complete workaround is available; users unable to upgrade should reject or remove double quotes from target paths and arguments, additionally reject shell metacharacters in versions 2.2.0 through 2.9.2 and 3.0.0-alpha.1 through 3.0.0-alpha.4, or bypass the PowerShell and Cmd wrappers and invoke target processes directly when handling untrusted input.

CliInvoke is a .NET library for invoking command-line programs, and its `CliInvoke.Specializations` packages provide specialized wrappers for shells such as PowerShell and Windows Command Prompt. `CliInvoke.Specializations` versions 2.2.0 through 2.8.4, 2.9.0 through 2.9.3, 2.10.0 through 2.10.4, 3.0.0-alpha.1 through 3.0.0-alpha.4, and 3.0.0-alpha.8 through 3.0.0-alpha.10, as well as `AlastairLundy.CliInvoke.Specializations` versions 1.0.0-rc.1 through 1.6.1.1, contain an OS command injection vulnerability in their PowerShell and Cmd wrappers. The wrappers pass a caller-controlled target and arguments to `pwsh -Command` or `cmd /c` using a single `ProcessStartInfo.Arguments` string, allowing a double quote in untrusted input to break operating-system-level quoting and cause the shell to execute an additional command with the host process's privileges. The vulnerability is patched in `CliInvoke.Specializations` versions 2.8.5, 2.9.4, 2.10.5, and 3.0.0-beta.1, and in `AlastairLundy.CliInvoke.Specializations` version 2.0.2. No complete workaround is available; users unable to upgrade should reject or remove double quotes from target paths and arguments, additionally reject shell metacharacters in versions 2.2.0 through 2.9.2 and 3.0.0-alpha.1 through 3.0.0-alpha.4, or bypass the PowerShell and Cmd wrappers and invoke target processes directly when handling untrusted input.

### Impact An OS command injection vulnerability exists in the PowerShell and Cmd shell wrappers provided by the `CliInvoke.Specializations` package (the `PowershellProcessInvoker`/`CmdProcessInvoker` invokers, and the `UsePowerShell`/`UseCmd` middleware in v3 pre-release versions). The wrappers re-run a caller-supplied target and arguments inside a shell command (`pwsh -Command ...` / `cmd /c ...`). In affected versions the wrapped command was delivered to the operating system as a single `ProcessStartInfo.Arguments` string. The OS command-line parser re-tokenizes that string before the shell parses it, so a double quote (`"`) in the target or arguments breaks OS-level quoting and lets the wrapped shell reassemble a second, unintended command. An attacker could exploit this to execute arbitrary commands with the privileges of the host process. ### Patches The Specializations Packages now deliver the command via `ProcessStartInfo.ArgumentList` (natively where supported, and polyfilled in older TFMs), so that the operating system passes argv verbatim and only the shell parses the command once. Upgrade to: - **2.8.5** (2.8.x line) - **2.9.4** (2.9.x line) - **2.10.5** (2.10.x line) - **3.0.0-beta.1** (3.x pre-release line) ### Workarounds No complete workaround is available. Until upgraded: - Reject or strip `"` from any target path or argument passed to the PowerShell/Cmd wrappers. On 2.2.0 – 2.9.2 and 3.0.0-alpha.1 – alpha.4, also reject shell metacharacters (`;`, `|`, `&`, `$`, backtick, parentheses). - Alternatively, bypass the wrappers for untrusted input and invoke the target process directly so that no second shell parse of the data occurs.