Skip to content

Add Host header validation to prevent DNS rebinding attacks #602

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
DaleSeo merged 3 commits into from
Feb 3, 2026
Merged

Add Host header validation to prevent DNS rebinding attacks #602

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
151bfb8
fix: add Host header validation to prevent DNS rebinding attacks
DaleSeo Jan 28, 2026
077181b
chore:changeset
DaleSeo Jan 28, 2026
5a35656
docs: add config options for host validation
DaleSeo Jan 28, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
16 changes: 16 additions & 0 deletions .changeset/host_validation.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,16 @@
---
default: minor
---

Add Host header validation to prevent DNS rebinding attacks. Requests with invalid Host headers are now rejected with 403 Forbidden. Enabled by default for StreamableHttp transport.

```yaml
transport:
type: streamable_http
host_validation:
enabled: true # default
allowed_hosts:
- mcp.dev.example.com
- mcp.staging.example.com
- mcp.example.com
```
Loading
Loading