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GHSA-7p85-w9px-jpjpcritical9.3

Twig: PHP code injection via `{% use %}` template name

Impact

Compiler::string() escapes ", $, \, NUL and TAB when generating PHP double-quoted string literals, but does not escape single quotes. In ModuleNode::compileConstructor(), the template name from a {% use %} tag is compiled via subcompile() -> string() and placed inside a surrounding PHP single-quoted string literal. A template name containing a single quote terminates that surrounding string early, allowing arbitrary PHP expressions to be injected into the compiled cache file.

Source excerpt · OSV

Affected packages

Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.

twig/twig Packagist
Affected rangeRecorded fix
Earlier releases before 3.26.0Ecosystem versions3.26.0

Version evidence: OSV · GHSA-7p85-w9px-jpjp

View original version evidence (242 explicit versions)

Original source description

Description

Compiler::string() escapes ", $, \, NUL and TAB when generating PHP double-quoted string literals, but does not escape single quotes. In ModuleNode::compileConstructor(), the template name from a {% use %} tag is compiled via subcompile() -> string() and placed inside a surrounding PHP single-quoted string literal. A template name containing a single quote terminates that surrounding string early, allowing arbitrary PHP expressions to be injected into the compiled cache file.

The injected code executes within the PHP process when the cache file is first loaded, bypassing the Twig sandbox entirely and achieving remote code execution. SecurityPolicy unconditionally allows {% use %} regardless of the configured allowedTags, so this primitive is reachable from sandboxed templates as well.

Resolution

Compiler::string() now also escapes single quotes so that template names placed inside single-quoted PHP literals can no longer break out of the surrounding context.

Credits

Twig would like to thank Anvil Secure in collaboration with Claude and Anthropic Research for reporting the issue and providing the fix.

References