CVE-2026-116676: Atlantis: OS command injection through PR-controlled Terraform workspace enables RCE during plan

Vulnerability summary

CVE-2026-116676 is a high (CVSS 8.8) vulnerability in runatlantis atlantis. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 40.3% of scored vulnerabilities.

Timeline

1. 27-10-2026
   PublishedVulnerability first disclosed.
2. 03-11-2026
   Last modifiedVulnerability information updated.

Description

Atlantis is a self-hosted golang application that listens for Terraform pull request events via webhooks. From version 0.4.0 until 0.47.1, Atlantis passes the pull-request-controlled workspace value from atlantis.yaml into Terraform command arguments that are joined with strings.Join(args, " ") and executed through sh -c. An authenticated contributor whose pull request is eligible for an Atlantis plan can include shell metacharacters in the workspace name, causing arbitrary commands to execute as the Atlantis service account without custom workflows, apply permission, or a malicious Terraform provider. External contributors can reach the flaw through fork pull requests only when --allow-fork-prs is enabled, while eligible same-repository branches do not require that option. The commands inherit the Atlantis process environment and can access cloud-provider, Terraform, and version-control credentials as well as files, state, and network resources available to the service. This issue is fixed in version 0.47.1.

• CWE-78Improper Neutralization of Special Elements used in an OS CommandThe product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command before it is sent to a downstream component.