v4.12.25
v4.12.25
View on GitHubView PackagePublished: Jun 9, 2026

Release Notes

Security fixes

This release includes fixes for the following security issues:

CORS Middleware reflects any Origin with credentials when origin defaults to the wildcard

Affects: hono/cors. Fixes the wildcard origin reflecting the request Origin and sending Access-Control-Allow-Credentials: true when credentials: true is set without an explicit origin, where any site a logged-in user visited could make credentialed cross-origin requests and read responses from cookie-authenticated endpoints. GHSA-88fw-hqm2-52qc

Body Limit Middleware can be bypassed on AWS Lambda by understating Content-Length

Affects: hono/body-limit on AWS Lambda (hono/aws-lambda, hono/lambda-edge). Fixes the request being built with the client-declared Content-Length while the body is delivered fully buffered, where a client could declare a small Content-Length with a much larger body and slip past the configured size limit. GHSA-rv63-4mwf-qqc2

Path traversal in serve-static on Windows via encoded backslash (%5C)

Affects: serveStatic on Windows (Node, Bun, Deno adapters). Fixes the path guard allowing a lone backslash, where an encoded backslash (%5C) decoded to \ was treated as a separator by the Windows path resolver, letting a single URL segment escape into a middleware-guarded subtree. GHSA-wwfh-h76j-fc44

Affects: hono/aws-lambda. Fixes multiple Set-Cookie response headers being joined into one comma-separated value for ALB single-header responses and VPC Lattice v2, where the value could not be split back into individual cookies and clients silently dropped or misparsed them. GHSA-j6c9-x7qj-28xf

Lambda@Edge adapter keeps only the last value of a repeated request header, dropping the rest

Affects: hono/lambda-edge. Fixes repeated request headers being written with overwrite instead of append, where only the last value of a header such as X-Forwarded-For reached the application and the remaining values were silently dropped. GHSA-wgpf-jwqj-8h8p