### Impact On POSIX, escapeshellarg(‘/usr/bin/wkhtmltopdf’) returns the literal string ‘/usr/bin/wkhtmltopdf’ with the single-quote characters included. is_executable() then looks for a file whose actual name contains those quote characters, which essentially never exists. The safe branch is dead code and $command always falls through to the raw, unescaped value. The rest of the arguments (options, input, output) are escaped correctly, so injection has to land in the binary string itself. That happens whenever the binary path is sourced from configuration that is user-influenced, derived from environment variables that ultimately come from request data, or concatenated with any user-controlled fragment. #### Proof of concept: ```php $pdf = new Knp\Snappy\Pdf(‘wkhtmltopdf; touch /tmp/snappy_rce’); $pdf->generate(‘https://example.com’, ‘/tmp/out.pdf’); // /tmp/snappy_rce is created. ``` **Impact:** command execution as the PHP process when the binary path is attacker-influenced. Even in deployments where the binary is hard-coded, this is a defensive-in-depth regression: downstream packages reasonably assume Snappy shell-escapes the binary because the code looks like it does. ### Patches The version 1.7.1 will resolve this security advisory. ### Workarounds Before calling the constructor, ensure `\is_executable($path)` is truthy. ```php // Bad example $pdf = new Knp\Snappy\Pdf('/path/to/binary'); ``` ```php // Better example $pathToBinary = '/path/to/binary'; if (!\is_executable($pathToBinary)) { throw new \RuntimeException(); } $pdf = new Knp\Snappy\Pdf('/path/to/binary'); ```
### Impact On POSIX, escapeshellarg(‘/usr/bin/wkhtmltopdf’) returns the literal string ‘/usr/bin/wkhtmltopdf’ with the single-quote characters included. is_executable() then looks for a file whose actual name contains those quote characters, which essentially never exists. The safe branch is dead code and $command always falls through to the raw, unescaped value. The rest of the arguments (options, input, output) are escaped correctly, so injection has to land in the binary string itself. That happens whenever the binary path is sourced from configuration that is user-influenced, derived from environment variables that ultimately come from request data, or concatenated with any user-controlled fragment. #### Proof of concept: ```php $pdf = new Knp\Snappy\Pdf(‘wkhtmltopdf; touch /tmp/snappy_rce’); $pdf->generate(‘https://example.com’, ‘/tmp/out.pdf’); // /tmp/snappy_rce is created. ``` **Impact:** command execution as the PHP process when the binary path is attacker-influenced. Even in deployments where the binary is hard-coded, this is a defensive-in-depth regression: downstream packages reasonably assume Snappy shell-escapes the binary because the code looks like it does. ### Patches The version 1.7.1 will resolve this security advisory. ### Workarounds Before calling the constructor, ensure `\is_executable($path)` is truthy. ```php // Bad example $pdf = new Knp\Snappy\Pdf('/path/to/binary'); ``` ```php // Better example $pathToBinary = '/path/to/binary'; if (!\is_executable($pathToBinary)) { throw new \RuntimeException(); } $pdf = new Knp\Snappy\Pdf('/path/to/binary'); ```
Update KnpLabs/knp-snappy to 1.7.1 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanSnappy: Binary path is never shell-escaped due to an inverted is_executable check affects KnpLabs/knp-snappy (composer). Severity is high. ### Impact On POSIX, escapeshellarg(‘/usr/bin/wkhtmltopdf’) returns the literal string ‘/usr/bin/wkhtmltopdf’ with the single-quote characters included. is_executable() then looks for a file whose actual name contains those quote characters, which essentially never exists. The safe branch is dead code and $command always falls through to the raw, unescaped value. The rest of the arguments (options, input, output) are escaped correctly, so injection has to land in the binary string itself. That happens whenever the binary path is sourced from configuration that is user-influenced, derived from environment variables that ultimately come from request data, or concatenated with any user-controlled fragment. #### Proof of concept: ```php $pdf = new Knp\Snappy\Pdf(‘wkhtmltopdf; touch /tmp/snappy_rce’); $pdf->generate(‘https://example.com’, ‘/tmp/out.pdf’); // /tmp/snappy_rce is created. ``` **Impact:** command execution as the PHP process when the binary path is attacker-influenced. Even in deployments where the binary is hard-coded, this is a defensive-in-depth regression: downstream packages reasonably assume Snappy shell-escapes the binary because the code looks like it does. ### Patches The version 1.7.1 will resolve this security advisory. ### Workarounds Before calling the constructor, ensure `\is_executable($path)` is truthy. ```php // Bad example $pdf = new Knp\Snappy\Pdf('/path/to/binary'); ``` ```php // Better example $pathToBinary = '/path/to/binary'; if (!\is_executable($pathToBinary)) { throw new \RuntimeException(); } $pdf = new Knp\Snappy\Pdf('/path/to/binary'); ```
AI coding agents often install or upgrade packages automatically in composer. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| KnpLabs/knp-snappycomposer | <=1.7.0 | 1.7.1 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate KnpLabs/knp-snappy to 1.7.1 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanSnappy: Binary path is never shell-escaped due to an inverted is_executable check affects KnpLabs/knp-snappy (composer). Severity is high. ### Impact On POSIX, escapeshellarg(‘/usr/bin/wkhtmltopdf’) returns the literal string ‘/usr/bin/wkhtmltopdf’ with the single-quote characters included. is_executable() then looks for a file whose actual name contains those quote characters, which essentially never exists. The safe branch is dead code and $command always falls through to the raw, unescaped value. The rest of the arguments (options, input, output) are escaped correctly, so injection has to land in the binary string itself. That happens whenever the binary path is sourced from configuration that is user-influenced, derived from environment variables that ultimately come from request data, or concatenated with any user-controlled fragment. #### Proof of concept: ```php $pdf = new Knp\Snappy\Pdf(‘wkhtmltopdf; touch /tmp/snappy_rce’); $pdf->generate(‘https://example.com’, ‘/tmp/out.pdf’); // /tmp/snappy_rce is created. ``` **Impact:** command execution as the PHP process when the binary path is attacker-influenced. Even in deployments where the binary is hard-coded, this is a defensive-in-depth regression: downstream packages reasonably assume Snappy shell-escapes the binary because the code looks like it does. ### Patches The version 1.7.1 will resolve this security advisory. ### Workarounds Before calling the constructor, ensure `\is_executable($path)` is truthy. ```php // Bad example $pdf = new Knp\Snappy\Pdf('/path/to/binary'); ``` ```php // Better example $pathToBinary = '/path/to/binary'; if (!\is_executable($pathToBinary)) { throw new \RuntimeException(); } $pdf = new Knp\Snappy\Pdf('/path/to/binary'); ```
AI coding agents often install or upgrade packages automatically in composer. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| KnpLabs/knp-snappycomposer | <=1.7.0 | 1.7.1 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard