CVE-2026-55431
Coder allows organizations to provision remote development environments via Terraform.
Does this matter?
Lower severity and a low EPSS score (0.34%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 6.1 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- EPSS
- 0.34% probability · 27th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-522, CWE-601
- Affected
- coder/coder
- Source
- security-advisories@github.com
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.