CVE-2026-39410: CWE-20: Improper Input Validation in honojs hono
A vulnerability in the honojs hono web application framework prior to version 4. 12. 12 allows bypass of cookie prefix protections due to inconsistent handling between browser cookie parsing and the parse() function. This discrepancy enables attacker-controlled cookies to override legitimate cookies by exploiting normalization differences. The issue is fixed in version 4. 12. 12. The vulnerability has a medium severity with a CVSS score of 4. 8.
AI Analysis
Technical Summary
CVE-2026-39410 describes an improper input validation vulnerability (CWE-20) in the honojs hono framework before version 4.12.12. The vulnerability arises because browser cookie parsing treats certain cookie names as distinct, but the framework's parse() function normalizes these names to the same key. This inconsistency allows an attacker to craft cookies that bypass prefix protections and override legitimate cookies. The issue is resolved in hono version 4.12.12.
Potential Impact
An attacker can bypass cookie prefix protections and override legitimate cookies, potentially leading to limited confidentiality and integrity impacts. The CVSS score of 4.8 reflects a medium severity with network attack vector, high attack complexity, no privileges required, no user interaction, and impacts on confidentiality and integrity but not availability.
Mitigation Recommendations
Upgrade honojs hono to version 4.12.12 or later where this vulnerability is fixed. No other official remediation or temporary fixes are indicated. Patch status is not explicitly stated beyond the fix in version 4.12.12, so users should verify the upgrade to this version to mitigate the issue.
CVE-2026-39410: CWE-20: Improper Input Validation in honojs hono
Description
A vulnerability in the honojs hono web application framework prior to version 4. 12. 12 allows bypass of cookie prefix protections due to inconsistent handling between browser cookie parsing and the parse() function. This discrepancy enables attacker-controlled cookies to override legitimate cookies by exploiting normalization differences. The issue is fixed in version 4. 12. 12. The vulnerability has a medium severity with a CVSS score of 4. 8.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-39410 describes an improper input validation vulnerability (CWE-20) in the honojs hono framework before version 4.12.12. The vulnerability arises because browser cookie parsing treats certain cookie names as distinct, but the framework's parse() function normalizes these names to the same key. This inconsistency allows an attacker to craft cookies that bypass prefix protections and override legitimate cookies. The issue is resolved in hono version 4.12.12.
Potential Impact
An attacker can bypass cookie prefix protections and override legitimate cookies, potentially leading to limited confidentiality and integrity impacts. The CVSS score of 4.8 reflects a medium severity with network attack vector, high attack complexity, no privileges required, no user interaction, and impacts on confidentiality and integrity but not availability.
Mitigation Recommendations
Upgrade honojs hono to version 4.12.12 or later where this vulnerability is fixed. No other official remediation or temporary fixes are indicated. Patch status is not explicitly stated beyond the fix in version 4.12.12, so users should verify the upgrade to this version to mitigate the issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-04-07T00:23:30.595Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69d672521cc7ad14da85d658
Added to database: 4/8/2026, 3:20:50 PM
Last enriched: 4/15/2026, 3:56:26 PM
Last updated: 5/23/2026, 10:14:23 PM
Views: 99
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