Summary

A previous fix for unsafe name handling in pbjs static / static-module code generation was incomplete. Affected versions of protobufjs-cli could still emit unsafe JavaScript references when generating static output from crafted JSON descriptor input. The common case of parsing schemas from .proto files is not affected.

This is a bypass of GHSA-6r35-46g8-jcw9 / CVE-2026-44295.

Impact

An attacker who can provide or influence pre-parsed JSON descriptors passed to pbjs static code generation may be able to cause generated JavaScript output to contain attacker-controlled code.

The injected code may execute if the generated file is later executed or imported and an affected generated API path is invoked.

Preconditions

• The application or build process must run pbjs static code generation on a pre-parsed JSON descriptor influenced by an attacker.
• The generated JavaScript file must subsequently be executed or imported.
• An affected generated API path must be invoked.

Workarounds

Do not run affected versions of pbjs static or static-module generation on untrusted JSON descriptors. If untrusted JSON descriptors must be accepted, validate descriptor-derived names before code generation and reject names that could not have been produced by parsing a valid .proto file. Running code generation in an isolated environment can reduce impact.

References

• GHSA-pr59-h9ph-3fr8
• https://nvd.nist.gov/vuln/detail/CVE-2026-54271