CVE-2026-55431
Description
Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, `coder open app` opens external workspace-app URLs without validating the scheme or host. When an external app URL contains the `$SESSION_TOKEN` placeholder the CLI replaces it with the user's real session token before handing the URL to the OS open handler. Practical exploitation requires the victim to run `coder open app` against a workspace whose external app definition the attacker controls. Only a malicious template author can control external app URLs. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 applies a URL-scheme allowlist in the CLI and limits `$SESSION_TOKEN` substitution to trusted destinations like the web frontend. As a workaround, avoid running `coder open app` for untrusted workspaces.
How to fix
- coder coder2.29.17, 2.32.7, 2.33.8, 2.34.2 or later
- github.com/coder/coder/v22.34.2, 2.33.8, 2.32.7, 2.29.17 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| coder coder | v < 2.29.17, 2.30.0 ≤ v < 2.32.7, 2.33.0 ≤ v < 2.33.8, 2.34.0 ≤ v < 2.34.2 | 2.29.17, 2.32.7, 2.33.8, 2.34.2 |
| github.com/coder/coder/v2Go | 2.34.0 ≤ v < 2.34.2, 2.33.0 ≤ v < 2.33.8, 2.30.0 ≤ v < 2.32.7, v < 2.29.17 | 2.34.2, 2.33.8, 2.32.7, 2.29.17 |
| github.com/coder/coderGo | No range specified | — |
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