CVE-2026-39409: CWE-180: Incorrect Behavior Order: Validate Before Canonicalize in honojs hono
Hono versions prior to 4. 12. 12 have a vulnerability in the ipRestriction() function where IPv4-mapped IPv6 addresses are not canonicalized before applying IPv4 allow or deny rules. This can cause IPv4 rules to fail to match correctly in dual-stack environments, potentially leading to unintended authorization behavior. The issue is fixed in version 4. 12. 12.
AI Analysis
Technical Summary
The vulnerability in honojs hono (CVE-2026-39409) arises from incorrect behavior order (CWE-180) where the ipRestriction() function does not canonicalize IPv4-mapped IPv6 client addresses before applying IPv4 access control rules. This affects versions prior to 4.12.12. In environments such as Node.js dual-stack, this can cause IPv4 allow or deny rules to be bypassed or misapplied, resulting in unintended authorization outcomes. The vulnerability has a CVSS 4.0 score of 6.3 (medium severity) and is fixed in version 4.12.12.
Potential Impact
The vulnerability can cause IPv4 allow or deny rules to fail to match IPv4-mapped IPv6 addresses, potentially allowing unauthorized access or denying legitimate access depending on the rules configured. This impacts authorization logic in applications using vulnerable versions of hono in dual-stack network environments.
Mitigation Recommendations
Upgrade to hono version 4.12.12 or later, where this vulnerability is fixed by proper canonicalization of IPv4-mapped IPv6 addresses before applying access control rules. Patch status is confirmed fixed in 4.12.12. No other mitigation is indicated.
CVE-2026-39409: CWE-180: Incorrect Behavior Order: Validate Before Canonicalize in honojs hono
Description
Hono versions prior to 4. 12. 12 have a vulnerability in the ipRestriction() function where IPv4-mapped IPv6 addresses are not canonicalized before applying IPv4 allow or deny rules. This can cause IPv4 rules to fail to match correctly in dual-stack environments, potentially leading to unintended authorization behavior. The issue is fixed in version 4. 12. 12.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in honojs hono (CVE-2026-39409) arises from incorrect behavior order (CWE-180) where the ipRestriction() function does not canonicalize IPv4-mapped IPv6 client addresses before applying IPv4 access control rules. This affects versions prior to 4.12.12. In environments such as Node.js dual-stack, this can cause IPv4 allow or deny rules to be bypassed or misapplied, resulting in unintended authorization outcomes. The vulnerability has a CVSS 4.0 score of 6.3 (medium severity) and is fixed in version 4.12.12.
Potential Impact
The vulnerability can cause IPv4 allow or deny rules to fail to match IPv4-mapped IPv6 addresses, potentially allowing unauthorized access or denying legitimate access depending on the rules configured. This impacts authorization logic in applications using vulnerable versions of hono in dual-stack network environments.
Mitigation Recommendations
Upgrade to hono version 4.12.12 or later, where this vulnerability is fixed by proper canonicalization of IPv4-mapped IPv6 addresses before applying access control rules. Patch status is confirmed fixed in 4.12.12. No other mitigation is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-07T00:23:30.594Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69d737041cc7ad14da419536
Added to database: 4/9/2026, 5:20:04 AM
Last enriched: 4/9/2026, 5:27:28 AM
Last updated: 4/9/2026, 7:42:25 AM
Views: 3
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