CVE-2026-55431
Last modified
CVE-2026-55431 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. 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. EPSS estimates a 0.40% chance of exploitation in the next 30 days.
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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Coder | Coder | < 2.29.17 |
| Coder | Coder | >= 2.30.0, < 2.32.7 |
| Coder | Coder | >= 2.33.0, < 2.33.8 |
| Coder | Coder | >= 2.34.0, < 2.34.2 |
References
- https://github.com/coder/coder/pull/26146Issue Tracking, Patch
- https://github.com/coder/coder/releases/tag/v2.29.17Release Notes
- https://github.com/coder/coder/releases/tag/v2.32.7Release Notes
- https://github.com/coder/coder/releases/tag/v2.33.8Release Notes
- https://github.com/coder/coder/releases/tag/v2.34.2Release Notes
- https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4gPatch, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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