GHSA-mmg6-4qmv-6pc8

Dashboard / Vulnerabilities / GHSA-mmg6-4qmv-6pc8

GHSA-mmg6-4qmv-6pc8

Summary: Infracost: Arbitrary file read via config-template readFile symlink traversal

Details: ### Impact Path traversal via link following in the Infracost config-template parser. The `readFile`, `pathExists`, `isDir`, and `matchPaths` template functions confined repo-supplied paths with a lexical `filepath.Rel` check plus a leaf-only `os.Lstat`: ``` {{ readFile "evil/file" }} ``` With an intermediate directory symlink committed in the repo (`evil -> /`), the path is lexically clean and the leaf is a regular file, so both checks pass, but `os.ReadFile` follows the symlink and reads outside the checkout. The contents are rendered into the generated config and surfaced via the Infracost dashboard and PR comment, so anyone who can open a pull request can read files off the runner. Affects `infracost` up to and including `v0.10.44`. Successful exploitation reads any file the CLI process can reach on the runner. Impact depends on what the run exposes: under `on: pull_request` (the configuration in Infracost's documentation) fork pull requests run without secrets and with a read-only token, so exposure is limited. If Infracost runs under `pull_request_target`, or is triggered by a same-repository pull request, the read reaches the repository's secrets, enabling secret theft. The patch confines all four functions regardless of trigger. ### Patches Fixed in `v0.10.45` ([#3586](https://github.com/infracost/infracost/pull/3586)) by routing all four functions through `security.IsPathAllowed`, which resolves symlinks anywhere in the path before a segment-aware containment check. The same fix landed in [config#14](https://github.com/infracost/config/pull/14) and [parser#144](https://github.com/infracost/parser/pull/144). - Installed via the official script, a package manager, or the `latest` Docker tag: upgrade to `v0.10.45` (or later) to receive the fix. - Pinned to a specific version or image digest: bump to `v0.10.45`. ### Workarounds No full fix without upgrading. To limit exposure: run Infracost under `on: pull_request` rather than `pull_request_target`, and keep fork pull requests from receiving secrets (the defaults).

References: https://github.com/infracost/infracost/security/advisories/GHSA-mmg6-4qmv-6pc8, https://nvd.nist.gov/vuln/detail/CVE-2026-71493, https://github.com/infracost/infracost/pull/3586, https://github.com/infracost/infracost/commit/4d39331afc0e27752d16d9d91c34583e5e8487fb, https://github.com/infracost/infracost, https://github.com/infracost/infracost/releases/tag/v0.10.45