GHSA-v54h-cp2w-9x4g: Coder's session token leaked to arbitrary hosts via `coder open app` for external workspace apps
The vulnerability in github.com/coder/coder/v2 involves the `coder open app` CLI command, which opens external workspace app URLs without validating the URL scheme or host. If the URL contains the placeholder `$SESSION_TOKEN`, the CLI replaces it with the user's real session token before opening the URL. This can lead to session token leakage to arbitrary hosts controlled by an attacker. Exploitation requires the user to run `coder open app` on a workspace with a malicious external app URL defined by an attacker-controlled workspace. The vulnerability allows full account impersonation for the token's lifetime. Fixes have been released that apply a URL scheme allowlist and restrict token substitution to trusted destinations.
AI Analysis
Technical Summary
`coder open app` in github.com/coder/coder/v2 replaces the `$SESSION_TOKEN` placeholder in external workspace app URLs with the user's real session token without validating the URL scheme or host. An attacker controlling a workspace's external app URL can craft a URL that exfiltrates the session token when the user runs this command, enabling full account impersonation. The vulnerability requires user interaction and control over the workspace's external app definition. The fix introduces a URL scheme allowlist and limits token substitution to trusted destinations. Patched versions include 2.34.2, 2.33.8, 2.32.7, and 2.29.17.
Potential Impact
An attacker who controls the external app URL in a workspace can cause the user's session token to be leaked to an arbitrary host when the user runs `coder open app`. This enables full account impersonation for the duration of the token's validity. The vulnerability requires the victim to run the command on a malicious workspace, so exploitation depends on user action and attacker control of workspace contents. The vulnerability does not affect availability but compromises confidentiality and integrity of the user's session.
Mitigation Recommendations
Apply the official patches by upgrading to one of the fixed versions: 2.34.2, 2.33.8, 2.32.7, or 2.29.17. Until patched, avoid running `coder open app` on untrusted workspaces to prevent session token leakage. The vendor has implemented a URL scheme allowlist and restricted token substitution to trusted destinations in these fixes.
GHSA-v54h-cp2w-9x4g: Coder's session token leaked to arbitrary hosts via `coder open app` for external workspace apps
Description
The vulnerability in github.com/coder/coder/v2 involves the `coder open app` CLI command, which opens external workspace app URLs without validating the URL scheme or host. If the URL contains the placeholder `$SESSION_TOKEN`, the CLI replaces it with the user's real session token before opening the URL. This can lead to session token leakage to arbitrary hosts controlled by an attacker. Exploitation requires the user to run `coder open app` on a workspace with a malicious external app URL defined by an attacker-controlled workspace. The vulnerability allows full account impersonation for the token's lifetime. Fixes have been released that apply a URL scheme allowlist and restrict token substitution to trusted destinations.
CVSS v3.1
Affected software
Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
`coder open app` in github.com/coder/coder/v2 replaces the `$SESSION_TOKEN` placeholder in external workspace app URLs with the user's real session token without validating the URL scheme or host. An attacker controlling a workspace's external app URL can craft a URL that exfiltrates the session token when the user runs this command, enabling full account impersonation. The vulnerability requires user interaction and control over the workspace's external app definition. The fix introduces a URL scheme allowlist and limits token substitution to trusted destinations. Patched versions include 2.34.2, 2.33.8, 2.32.7, and 2.29.17.
Potential Impact
An attacker who controls the external app URL in a workspace can cause the user's session token to be leaked to an arbitrary host when the user runs `coder open app`. This enables full account impersonation for the duration of the token's validity. The vulnerability requires the victim to run the command on a malicious workspace, so exploitation depends on user action and attacker control of workspace contents. The vulnerability does not affect availability but compromises confidentiality and integrity of the user's session.
Mitigation Recommendations
Apply the official patches by upgrading to one of the fixed versions: 2.34.2, 2.33.8, 2.32.7, or 2.29.17. Until patched, avoid running `coder open app` on untrusted workspaces to prevent session token leakage. The vendor has implemented a URL scheme allowlist and restricted token substitution to trusted destinations in these fixes.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-v54h-cp2w-9x4g
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-55431"]
- Ecosystems
- ["Go"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a4c340327e9c797195f5f36
Added to database: 07/06/2026, 23:02:27 UTC
Last enriched: 07/06/2026, 23:12:20 UTC
Last updated: 07/06/2026, 23:12:20 UTC
Views: 2
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.