CVE-2025-71381
Hono - Vary Header Injection in CORS Middleware
- State
- Published
- Severity
- 6.9 Medium
- Published
- Jun 30, 2026
- Updated
- Oct 29, 2026
- Reserved
- Jun 20, 2026
Description
Hono before 4.10.3 contains a flaw in its CORS middleware: when the origin is not set to "*", the middleware copies the Vary header from the incoming request into the response. Because Vary is a response header that should be managed by the server, an attacker can supply arbitrary Vary values that are reflected into the response, potentially causing cache key pollution and inconsistent CORS enforcement in environments that rely on shared caches or proxies.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 6.9 Medium | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 6.5 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N | VulnCheck |
Weaknesses
- CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting')
Affected Products
| Product | Versions |
|---|---|
HonoHono |
|
References
- GitHub Security Advisory (GHSA-q7jf-gf43-6x6p)vendor-advisory
- VulnCheck Advisory: Hono - Vary Header Injection in CORS Middlewarethird-party-advisory
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