Nuclei: Arbitrary Command Execution via DAST Code Signature Bypass

A vulnerability in Nuclei's DAST template loading path allows unsigned `code:` protocol templates to execute, bypassing the cryptographic signature requirement that is meant to prevent arbitrary command execution from untrusted templates. **Affected Component** The issue is in the template loader's DAST loading branch. When `-dast` is enabled and a template contains a `fuzzing:` block, the loader accepted the template through a code path that omitted the unsigned-code-template signature check present in the normal loading branch. **Description** Nuclei requires `code:` protocol templates to be cryptographically signed before execution. Unsigned code templates are normally skipped with a warning. However, when a template combined a `fuzzing:` block (making it DAST-eligible) with an unsigned `code:` block, enabling `-dast` routed the template through the DAST loader branch, which did not enforce signature verification. For multiprotocol templates containing both HTTP and `code:` blocks, the unsigned code request was included in the execution queue regardless of whether `-code` was set. This allowed arbitrary shell command execution from an unsigned `code:` block with only `-dast` enabled. > [!NOTE] Both DAST mode (`-dast`) and code-protocol templates are disabled by default. Code templates normally require both the `-code` flag and a valid template signature. This issue bypassed the signature and `-code` controls only when `-dast` was explicitly enabled. **Affected Users** - **