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Medium, CVSS 5.9amended

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

CVE-2026-71493GHSA-mmg6-4qmv-6pc8

What to do

Vendor fix available. Upgrade each affected package to the fixed version on its release line (github.com/infracost/infracost 0.10.45), redeploy, then verify what is actually installed.

This page has no inventory attached, so it cannot say whether you are affected. A vendor fix is not proof that your deployment is fixed.

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Affected packages

Sources

Severity and exploitation
Exploitation
No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.
CVSS 4.0
5.9 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N · score source
EPSS
  • CVE-2026-71493: 0.54% estimated exploitation activity in the next 30 days; percentile 45.74 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.
Source description

As published by the source; long descriptions are shortened.

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: 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: pullrequest (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…

Dates and revisions
Published by the source
Last modified by the source
Source last checked
  1. Revision 4 · amended ·

    Amended from ghsa record GHSA-mmg6-4qmv-6pc8

  2. Revision 3 · amended ·

    Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

  3. Revision 2 · amended ·

    Amended from osv record GO-2026-6439

  4. Revision 1 · created ·

    Published from osv record GHSA-mmg6-4qmv-6pc8

Agent brief

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# Patch Next advisory brief: CVE-2026-71493

Advisory: Infracost: Arbitrary file read via config-template readFile symlink traversal
IDs: CVE-2026-71493, GHSA-mmg6-4qmv-6pc8
Record: https://patchnext.com/advisories/cve-2026-71493 (revision 4, source checked 26 Oct 2026, 15:29 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/infracost/infracost 0.10.45. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/infracost/infracost: affected < 0.10.45; fixed in 0.10.45

## Suggested inspection (read-only)
- Go github.com/infracost/infracost: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/infracost/infracost.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-mmg6-4qmv-6pc8 (OSV record GHSA-mmg6-4qmv-6pc8 lists affected ranges: Go github.com/infracost/infracost >=0 <0.10.45 (fixed))
- Verified: https://osv.dev/vulnerability/GO-2026-6439 (OSV record GO-2026-6439 lists affected ranges: Go github.com/infracost/infracost >=0 <0.10.45 (fixed))
- Verified: https://github.com/advisories/GHSA-mmg6-4qmv-6pc8 (GitHub-reviewed advisory GHSA-mmg6-4qmv-6pc8 lists affected ranges: Go github.com/infracost/infracost >=0 <0.10.45)

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