CVE-2026-100368

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.

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.