Hono has incorrect IP matching in ipRestriction() for IPv4-mapped IPv6 addresses
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.
Summary
Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.12, ipRestriction() does not canonicalize IPv4-mapped IPv6 client addresses (e.g. ::ffff:127.0.0.1) before applying IPv4 allow or deny rules. In environments such as Node.js dual-stack, this can cause IPv4 rules to fail to match, leading to unintended authorization behavior. This vulnerability is fixed in 4.12.12.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| honojs | hono | before 4.12.12 | 4.12.12 | Patch available | CNA |
| — | hono (npm) | before 4.12.12 | 4.12.12 | Patch available | GHSA-xpcf-pg52-r92g |
- hono Vendorhonojs Affected before 4.12.12 Fixed in 4.12.12 Patch available CNA
- hono (npm) Vendor— Affected before 4.12.12 Fixed in 4.12.12 Patch available GHSA-xpcf-pg52-r92g
Remediation
- Fix · CNA hono (honojs) Fixed in 4.12.12
- Fix · GHSA-xpcf-pg52-r92g hono (npm) Fixed in 4.12.12 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-39409
- 2026-10-03 Alias added: GHSA-xpcf-pg52-r92g
References
Advisory 2
More honojs Hono vulnerabilities
- TI-2024-21741 Hono vulnerable to Restricted Directory Traversal in serveStatic with deno CVSS 3.1MEDIUM 5.3
- TI-2024-32610 Hono vulnerable to bypass of CSRF Middleware by a request without Content-Type header. CVSS 3.1MEDIUM 5.9
- TI-2024-29381 Hono CSRF middleware can be bypassed using crafted Content-Type header CVSS 3.1MEDIUM 5.0
- TI-2026-23190 Hono: Arbitrary file access via serveStatic vulnerability CVSS 3.1CRITICAL 9.8
- TI-2026-22076 Hono is Vulnerable to Authentication Bypass by IP Spoofing in AWS Lambda ALB conninfo CVSS 3.1HIGH 8.2
- TI-2026-18334 JWT algorithm confusion in Hono JWK Auth Middleware when JWK lacks "alg" (untrusted header.alg fallback) CVSS 3.1HIGH 8.2
Sources
- CVE-2026-39409 · CVE Program
- CVE-2026-39409 · NVD
- FIRST EPSS
- GHSA-xpcf-pg52-r92g · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences