PT-2026-39327 · Npm · Hono

Published 2026-05-09 · Updated 2026-05-09 · CVE-2026-44457

OSV

CVSS v3.1

5.3

Medium

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Summary

Cache Middleware does not skip caching for responses that declare per-user variance via Vary: Authorization or Vary: Cookie. As a result, a response cached for one authenticated user may be served to subsequent requests from different users.

Details

The Cache Middleware skips caching when a response carries Vary: *, certain Cache-Control directives (private, no-store, no-cache), or Set-Cookie. However, Vary: Authorization and Vary: Cookie — the standard signals defined in RFC 9110 / RFC 9111 to indicate per-user responses — are not treated as cache-skip reasons.

This issue arises when applications use the Cache Middleware on endpoints that return user-specific data and rely on Vary: Authorization or Vary: Cookie to scope the response per user, without also setting Cache-Control: private.

Impact

A user may receive a cached response that was originally generated for a different authenticated user. This may lead to:

• Disclosure of personally identifiable information or other user-specific data present in the response body
• Inconsistent or incorrect behavior in user-specific endpoints

This issue affects applications that use the Cache Middleware on endpoints whose responses vary by Authorization or Cookie and that do not also set Cache-Control: private.

Fix

Weakness Enumeration

CWE-524

Related Identifiers

CVE-2026-44457

GHSA-P77W-8QQV-26RM

Affected Products

Hono

References · 3

• https://osv.dev/vulnerability/GHSA-p77w-8qqv-26rm · Vendor Advisory
• https://github.com/honojs/hono · Note
• https://github.com/honojs/hono/security/advisories/GHSA-p77w-8qqv-26rm · Note