CVE-2026-55431: coder Insufficiently Protected Credentials

Vulnerability summary

CVE-2026-55431 is a high (CVSS 7.7) Insufficiently Protected Credentials vulnerability in coder. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 25.5% of scored vulnerabilities.

Timeline

1. 08-07-2026
   PublishedVulnerability first disclosed.
2. 08-07-2026
   Last modifiedVulnerability information updated.

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.

• CWE-522Insufficiently Protected CredentialsThe product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.
• CWE-601URL Redirection to Untrusted Site ('Open Redirect')The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.