CVE-2025-58362: Hono Path Traversal Vulnerability

CVE-2025-58362 Overview

CVE-2025-58362 is a path confusion vulnerability affecting Hono, a popular Web application framework that provides support for any JavaScript runtime. The vulnerability exists in the getPath utility function and could allow attackers to bypass proxy-level Access Control Lists (ACLs) such as Nginx location blocks. This authorization bypass vulnerability affects Hono versions 4.8.0 through 4.9.5 and has been addressed in version 4.9.6.

Critical Impact

Unauthorized access to protected endpoints (e.g., /admin) could expose sensitive administrative data, potentially leading to full application compromise.

Affected Products

• Hono versions 4.8.0 through 4.9.5
• Hono for Node.js runtime environments
• Applications using proxy-level ACLs with vulnerable Hono versions

Discovery Timeline

• 2025-09-05 - CVE CVE-2025-58362 published to NVD
• 2025-09-17 - Last updated in NVD database

Technical Details for CVE-2025-58362

Vulnerability Analysis

The vulnerability stems from a flaw in how the getPath utility function parses request URLs. The original implementation relied on fixed character offsets when extracting paths from request URIs. When handling certain malformed absolute-form Request-URIs, this approach could result in incorrect path extraction, creating a path confusion condition.

This path confusion can be exploited to bypass proxy-level access controls. For example, if an Nginx reverse proxy is configured with location blocks to restrict access to sensitive endpoints like /admin, an attacker could craft a malformed request URI that causes Hono to interpret the path differently than the proxy. The proxy would allow the request through based on its interpretation, while Hono would route it to a restricted endpoint based on its flawed path extraction.

The confidentiality impact varies depending on what data is exposed behind the protected endpoints. If sensitive administrative data or privileged functionality is accessible, the impact could be severe.

Root Cause

The root cause is improper input validation and inconsistent path parsing in the getPath utility function (CWE-706: Use of Incorrectly-Resolved Name or Reference). The function used fixed character offsets to parse URLs rather than properly handling all valid and malformed URI formats, leading to discrepancies between how the proxy and application interpret the same request path.

Attack Vector

The attack is network-accessible and requires no authentication or user interaction. An attacker can craft malformed absolute-form Request-URIs that exploit the path parsing discrepancy between a reverse proxy (such as Nginx) and the Hono application. This enables unauthorized access to endpoints that should be protected by proxy-level ACL rules.

The attack flow involves:

1. Identifying a target application using Hono behind a reverse proxy with ACL-protected paths
2. Crafting a malformed absolute-form Request-URI that bypasses the proxy's location block matching
3. The proxy forwards the request believing it targets an allowed path
4. Hono's flawed getPath function extracts a different path, routing the request to a protected endpoint

Detection Methods for CVE-2025-58362

Indicators of Compromise

• Unusual or malformed absolute-form Request-URIs in web server access logs
• Unexpected access attempts to administrative endpoints (/admin, /api/admin, etc.) from unauthorized sources
• Discrepancies between proxy logs and application logs regarding requested paths
• Access log entries showing successful requests to protected endpoints without corresponding authentication events

Detection Strategies

• Implement log correlation between reverse proxy logs and application logs to identify path interpretation discrepancies
• Deploy Web Application Firewall (WAF) rules to detect malformed absolute-form Request-URIs
• Monitor for requests containing unusual URI encoding or path manipulation patterns
• Enable verbose logging in both the proxy layer and Hono application to capture full request details

Monitoring Recommendations

• Audit access patterns to sensitive endpoints for any anomalous traffic from unexpected sources
• Set up alerts for access to administrative endpoints that don't follow expected authentication flows
• Review Hono dependency versions across all applications in your environment
• Implement runtime application self-protection (RASP) to detect path traversal and confusion attacks

How to Mitigate CVE-2025-58362

Immediate Actions Required

• Upgrade Hono to version 4.9.6 or later immediately
• Review access logs for any signs of exploitation targeting protected endpoints
• Audit proxy ACL configurations to ensure defense-in-depth beyond the application layer
• Implement additional authentication checks at the application level for sensitive endpoints

Patch Information

The vulnerability has been fixed in Hono version 4.9.6. The fix addresses the path parsing logic in the getPath utility function to properly handle absolute-form Request-URIs. The patch is available via the GitHub Release v4.9.6. For technical details on the changes, review the GitHub Commit and the GitHub Security Advisory GHSA-9hp6-4448-45g2.

Workarounds

• Implement application-level authentication and authorization checks for all sensitive endpoints rather than relying solely on proxy ACLs
• Add duplicate access control rules in the Hono application to validate paths independently of proxy configuration
• Consider normalizing request paths at the proxy layer before forwarding to the application
• Deploy a WAF with rules to block requests containing malformed absolute-form URIs

# Update Hono to the patched version
npm update hono@4.9.6

# Or specify the exact version in package.json
npm install hono@^4.9.6 --save