CVE-2026-116676 runatlantis CVE debrief

Who should care

Defenders responsible for securing Atlantis deployments, especially those with contributors having access to plans, should assess exposure and prioritize verification of their environment's configurations and access controls.

Why it matters

Defenders should care about CVE-2026-116676 because it allows contributors to execute arbitrary commands as the Atlantis service account, potentially leading to RCE, credential exposure, and lateral movement within the environment.

• Potential for RCE during Atlantis plan execution
• Exposure of cloud-provider, Terraform, and VCS credentials
• Lateral movement within the environment
• Data tampering and unauthorized access

Technical summary

The vulnerability exists in Atlantis, where the Terraform `workspace` value from a pull request's `atlantis.yaml` is passed into a shell command without quoting or escaping. This allows a contributor to include shell metacharacters in the workspace name and execute arbitrary commands as the Atlantis service account. The executed command inherits the Atlantis process environment, which commonly contains cloud-provider, Terraform, and VCS credentials, potentially leading to RCE, credential exposure, and lateral movement within the environment.

Defensive priority

Defenders should prioritize verifying exposure in their environment, especially where contributors have access to Atlantis plans, and assess the feasibility of exploitation given their specific configurations and access controls.

Recommended defensive actions

• Verify exposure in environments where contributors have access to Atlantis plans
• Assess the feasibility of exploitation given specific configurations and access controls
• Restrict contributor access to sensitive data and systems
• Implement additional security measures to monitor and control Atlantis usage
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The vulnerability was verified against the current `upstream/main` commit `92ce5c51d1a050357e44df3535483425e59fa984` on August 13, 2026. The vulnerable data flow involves validating the PR-controlled project workspace in `server/core/config/raw/project.go` and passing it directly as a Terraform command argument in `server/core/runtime/workspaces.go`.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.