Follows #28340, now merged. `smtp.go` renders the notification title through `PlaintextFromMarkdown`, which strips Markdown **and decodes HTML entities**, then stores the result in `Labels["_subject"]`. `html.gotmpl` interpolated that raw into `<title>` and `<h1>`, so an entity-encoded payload in a user-controlled label arrived as live markup: ``` template_display_name = <a href="https://attacker.example/login">Re-authenticate now</a> -> <title>Template "<a href="https://attacker.example/login">Re-authenticate now</a>" deleted</title> ``` Markdown escaping cannot reach this. `&` is not backslash-escapable in either renderer, and this path never enters gomarkdown, so neither `html.SkipHTML` nor the `Safelink` added in #28340 sees the string. `{{ .UserName }}` was interpolated raw at the same template, straight from the unescaped payload the dispatcher receives. This PR adds `| html` to seven values across eleven positions in `html.gotmpl`: | Value | Positions | Why | |---|---|---| | `.Labels._subject` | 2 | the injection above, in `<title>` and `<h1>` | | `.UserName` | 1 | reaches the template straight from the unescaped payload | | `$action.URL` | 1 | rendered from user data at `enqueuer.go:201`; `EscapedForMarkdown` does not touch `Actions` | | `$action.Label` | 1 | static today, escaped so it stays safe if that changes | | `base_url` | 4 | `--access-url` is scheme-checked only, so a `"` closes the `href` | | `current_year` | 1 | cannot carry markup, escaped so the rule has no exceptions | | `.NotificationTemplateID` | 1 | same | `logo_url` and `app_name` were already escaped in #28340. `{{ .Labels._body }}` stays unescaped: it is intentionally gomarkdown output, and it is the only value in the file that is not escaped. The action and `base_url` values are defense in depth rather than open holes. A `"` in an action URL fails closed at enqueue, because the rendered actions JSON is unmarshalled before use and the quote breaks that parse; `<`, `>`, `&` and `'` survive but are inert inside a double-quoted attribute. `base_url` requires an operator to set a hostile `--access-url`. Every value is guarded by a test. Removing `| html` from any of the nine escaped values now fails a named test, verified by removing each pipe in turn: - `TestSMTPHTMLTemplateEscapesUntrustedValues` covers `_subject`, `UserName` and both action values. - `TestSMTPHTMLTemplateEscapesTrustedValues` covers `base_url`, `current_year` and `.NotificationTemplateID`, none of which can carry markup in production, so no golden file would catch their regression. - `TestSMTPHTMLTemplateEscapesAppearanceHelpers` covers `logo_url` and `app_name`. That last point is why the trusted values needed tests rather than goldens: escaping them costs zero golden churn, so nothing already in the tree fails when it is removed. Before this PR the same was true of `$action.Label`, whose escaping could be deleted with no golden diff and no failing test at all. The 36 golden files change by entity encoding only, mostly `"` to `"` and `'` to `'` in subjects. Verified by quoted-printable decoding every file before and after and confirming the two are identical once HTML entities are decoded: 36/36 with no semantic difference. Escaping `base_url`, `current_year` and `.NotificationTemplateID` added no further churn. **NOTE**: `$action.URL | html` turns the `&` in the one-time passcode reset link into `&`. That is the correct encoding of a literal `&` in an attribute value, and every conformant client decodes it before navigating, so the request the server receives is unchanged. It is the only golden change with behavior attached. Migrating this template to `html/template` was considered and declined; the reasoning and the conditions that would reverse it are on the CRF-3 review thread. Refs https://linear.app/codercom/issue/PLAT-273/markdown-link-injection-into-admin-notification-emails-sec-93
Coder is a self-hosted platform for cloud development environments and AI coding agents. Workspaces are defined with Terraform, connected through a secure Wireguard® tunnel, and automatically shut down when not used. Coder Agents runs a native AI coding agent whose loop executes in the control plane on your infrastructure, with no API keys in workspaces.
- Define cloud development environments in Terraform
- EC2 VMs, Kubernetes Pods, Docker Containers, etc.
- Automatically shutdown idle resources to save on costs
- Onboard developers in seconds instead of days
- Delegate coding work to AI agents on your infrastructure
- Bring any model (Anthropic, OpenAI, Google, Bedrock, self-hosted)
- No LLM credentials in workspaces, user identity on every action
- Centralized model governance, cost tracking, and audit logging
Quickstart
Check out our install guides for other methods and a complete tutorial.
Try Coder with the install script on Linux and macOS, or grab the latest binary or installer from GitHub Releases on Windows:
curl -L https://coder.com/install.sh | sh
Start the server and open http://localhost:3000 to create your initial user, create a Docker template, and provision your first workspace:
coder server
For a production deployment, add a PostgreSQL database (version 13 or later) and an external access URL, and see our validated architectures for sizing and infrastructure guidance:
coder server --postgres-url <url> --access-url <url>
Without these flags, Coder uses a built-in database and sets up a *.try.coder.app access URL for evaluation. Use coder --help for the full list of flags and environment variables.
Documentation
Browse the documentation or visit a specific section below:
- Workspaces: Workspaces contain the IDEs, dependencies, and configuration information needed for software development
- Templates: Templates are written in Terraform and describe the infrastructure for workspaces
- Coder Agents: Delegate coding work to AI agents running on your self-hosted infrastructure
- AI Gateway: Centralize authentication, auditing, and cost controls for AI tooling
- Administration: Learn how to operate Coder
- Premium: Learn about paid features built for large teams
- IDEs: Connect your existing editor to a workspace
Support
Open an issue for bugs and feature requests.
For community support, showcasing what you built, and feedback on in-progress features, join our Discord or GitHub Discussions.
Dedicated support is included in Coder Premium. For more information, visit coder.com/pricing.
Integrations
New integrations are always in progress. Open an issue to request one. Contributions are welcome in any official or community repository.
Official
- Coder Registry: Templates, modules, and integrations for common development environments
- Coding Agents: Run agents like Claude Code, Codex, and OpenCode isolated in Coder workspaces
- coderd Terraform Provider: Declaratively manage your Coder deployment configuration as code
- VS Code Extension: Open any Coder workspace in VS Code with a single click
- JetBrains Toolbox Plugin: Open any Coder workspace from JetBrains Toolbox with a single click
- Dev Containers: Build development environments using
devcontainer.jsonon Docker, Kubernetes, and OpenShift - Kubernetes Log Stream: Stream Kubernetes Pod events to the Coder startup logs
- Self-Hosted VS Code Extension Marketplace: A private extension marketplace that works in restricted or airgapped networks integrating with code-server.
- GitHub Actions: An action to set up the Coder CLI in GitHub workflows
Community
- Coder Discord: Chat with the community, get support, and hear about new product updates first
- Community Templates: Community-contributed workspace templates in the Coder Registry
- Community Modules: Community-contributed modules to extend Coder templates
- Coder Template GitHub Action: A GitHub Action that updates Coder templates
- Coder Agents Chat Action: A GitHub Action that starts a Coder Agents chat against a GitHub issue or pull request
Contributing
New contributors are always welcome. If you are new to the Coder codebase, see the contribution guide to get started.
Hiring
Apply on the careers page if you are interested in joining the team.
