starlet supports Go 1.19 and keeps the ecosystem interpreter baseline at go.starlark.net v0.0.0-20260324133313-ffb3f39dd27a. Build production applications with a supported Go toolchain containing current security fixes. Keeping a library compatible with Go 1.19 does not make that old toolchain a recommended production compiler.

The pinned interpreter predates the upstream parser recursion fix described in google/starlark-go commit 5395d018f003 (GHSA-wcqm-92f8-mh2v). Excessively nested source can exhaust the Go stack and terminate the host process. This release retains that known limitation to preserve the established interpreter and Go compatibility baseline; it does not claim to fix the vulnerability.

The boundary covers direct source, readers, files, compilation or checking, and every module loaded through load(). Source must be selected and reviewed by the host, including generated code and loaded modules. Data accepted by a trusted script is not permission to evaluate that data as new source.

Execution-step limits, cancellation, timeouts, capability gates and recover do not prevent a fatal stack overflow during parsing. An input-size limit can reduce exposure but is not a complete substitute for a parser recursion limit. Documentation states this boundary; it does not remove the vulnerable code.

For attacker-controlled source, the host needs a separately reviewed deployment with process isolation and external CPU, memory, time and output limits, or an explicit interpreter upgrade/backport with compatibility testing. Those are host changes, not protections supplied by this package. A newer Go compiler alone does not patch the old interpreter. The library is not an in-process security boundary for untrusted or multi-tenant script execution.

Go module requirements are minimum versions: another dependency can select a newer interpreter through minimal version selection. Hosts should verify the actual selection with go list -m go.starlark.net and review any change. An application's replace directive is local to that application and does not provide a backport to consumers of this library.

Report vulnerabilities privately through GitHub security advisories. Use synthetic examples without credentials or business data. No response-time SLA is promised.