Key Points
- Fixes CORS wildcard origin with credentials
- Prevents body-limit bypass on AWS Lambda
- Resolves cookie/header and Windows path traversal issues
Summary
This release (v4.12.25) contains multiple security fixes across middleware and platform adapters. It addresses CORS origin reflection with credentials, body-size enforcement bypasses on AWS Lambda, a Windows path-traversal in serve-static, and header/cookie handling bugs in AWS Lambda and Lambda@Edge adapters.
Key Points
- CORS middleware: fixed wildcard-origin behavior that reflected the request Origin and sent Access-Control-Allow-Credentials: true when credentials: true was set without an explicit origin (hono/cors, GHSA-88fw-hqm2-52qc). Action: specify an explicit origin or upgrade.
- Body Limit: fixed bypass on AWS Lambda where client-declared Content-Length could understate a larger buffered body (hono/body-limit; hono/aws-lambda, hono/lambda-edge, GHSA-rv63-4mwf-qqc2). Action: upgrade to enforce limits correctly on Lambda adapters.
- serve-static (Windows): fixed path traversal via encoded backslash (%5C) that decoded to a lone backslash and escaped middleware guards (Node/Bun/Deno adapters, GHSA-wwfh-h76j-fc44). Action: upgrade and validate static-serving paths on Windows.
- AWS Lambda cookies: fixed multiple Set-Cookie headers being merged into one comma-separated header for ALB single-header and VPC Lattice v2 responses, which caused dropped/misparsed cookies (hono/aws-lambda, GHSA-j6c9-x7qj-28xf). Action: upgrade and test cookie behavior behind ALB/Lattice.
- Lambda@Edge headers: fixed repeated request headers being overwritten instead of appended (hono/lambda-edge, GHSA-wgpf-jwqj-8h8p). Action: upgrade and verify multi-valued headers like X-Forwarded-For are preserved.
Recommended Actions
- Upgrade to v4.12.25 as soon as possible.
- Audit places that rely on default CORS origins with credentials; prefer explicit origins.
- Re-test body-size limits and streaming behavior on AWS Lambda deployments.
- Validate static file serving on Windows (check for encoded backslash vectors).
- Test Set-Cookie behavior behind ALB and VPC Lattice, and repeated request headers for Lambda@Edge.
References
- Release: v4.12.25 (published 2026-06-09)
- GHSA advisories listed above for each fix