GHSA-mmg6-4qmv-6pc8 Infracost: Arbitrary file read via config-template readFile symlink traversal

• Go github.com/infracost/infracost: < 0.10.45 → fixed in 0.10.45

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) 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 and parser#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).