GHSA-R354-F388-2FHH

Vulnerability from github – Published: 2026-01-27 19:01 – Updated: 2026-01-29 03:39
VLAI?
Summary
Hono IPv4 address validation bypass in IP Restriction Middleware allows IP spoofing
Details

Summary

IP Restriction Middleware in Hono is vulnerable to an IP address validation bypass. The IPV4_REGEX pattern and convertIPv4ToBinary function in src/utils/ipaddr.ts do not properly validate that IPv4 octet values are within the valid range of 0-255, allowing attackers to craft malformed IP addresses that bypass IP-based access controls.

Details

The vulnerability exists in two components:

  1. Permissive regex pattern: The IPV4_REGEX (/^[0-9]{0,3}\.[0-9]{0,3}\.[0-9]{0,3}\.[0-9]{0,3}$/) accepts octet values greater than 255 (e.g., 999).
  2. Unsafe binary conversion: The convertIPv4ToBinary function does not validate octet ranges before performing bitwise operations. When an octet exceeds 255, it overflows into adjacent octets during the bit-shift calculation.

For example, the IP address 1.2.2.355 is accepted and converts to the same binary value as 1.2.3.99:

  • 355 = 256 + 99 = 0x163
  • After bit-shifting: (1 << 24) + (2 << 16) + (2 << 8) + 355 = 0x01020363 = 1.2.3.99

Impact

An attacker can bypass IP-based restrictions by crafting malformed IP addresses:

  • Blocklist bypass: If 1.2.3.0/24 is blocked, an attacker can use 1.2.2.355 (or similar) to bypass the restriction.
  • Allowlist bypass: Requests from unauthorized IP ranges may be incorrectly permitted.

This is exploitable when the application relies on client-provided IP addresses (e.g., X-Forwarded-For header) for access control decisions.

Affected Components

  • IP Restriction Middleware
  • src/utils/ipaddr.ts: IPV4_REGEX, convertIPv4ToBinary, distinctRemoteAddr
Severity ?
4.8 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "hono"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "4.11.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-24398"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-185"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-27T19:01:43Z",
    "nvd_published_at": "2026-01-27T19:16:16Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nIP Restriction Middleware in Hono is vulnerable to an IP address validation bypass. The `IPV4_REGEX` pattern and `convertIPv4ToBinary` function in `src/utils/ipaddr.ts` do not properly validate that IPv4 octet values are within the valid range of 0-255, allowing attackers to craft malformed IP addresses that bypass IP-based access controls.\n\n## Details\n\nThe vulnerability exists in two components:\n\n1. **Permissive regex pattern:** The `IPV4_REGEX (/^[0-9]{0,3}\\.[0-9]{0,3}\\.[0-9]{0,3}\\.[0-9]{0,3}$/)` accepts octet values greater than 255 (e.g., `999`).\n2. **Unsafe binary conversion:** The `convertIPv4ToBinary` function does not validate octet ranges before performing bitwise operations. When an octet exceeds 255, it overflows into adjacent octets during the bit-shift calculation.\n\nFor example, the IP address `1.2.2.355` is accepted and converts to the same binary value as 1.2.3.99:\n\n* `355` = `256 + 99` = `0x163`\n* After bit-shifting: `(1 \u003c\u003c 24) + (2 \u003c\u003c 16) + (2 \u003c\u003c 8) + 355` = `0x01020363` = `1.2.3.99`\n\n## Impact\n\nAn attacker can bypass IP-based restrictions by crafting malformed IP addresses:\n\n* **Blocklist bypass:** If `1.2.3.0/24` is blocked, an attacker can use `1.2.2.355` (or similar) to bypass the restriction.\n* **Allowlist bypass:** Requests from unauthorized IP ranges may be incorrectly permitted.\n\nThis is exploitable when the application relies on client-provided IP addresses (e.g., `X-Forwarded-For header`) for access control decisions.\n\n## Affected Components\n\n* IP Restriction Middleware\n* `src/utils/ipaddr.ts`: `IPV4_REGEX`, `convertIPv4ToBinary`, `distinctRemoteAddr`",
  "id": "GHSA-r354-f388-2fhh",
  "modified": "2026-01-29T03:39:00Z",
  "published": "2026-01-27T19:01:43Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/security/advisories/GHSA-r354-f388-2fhh"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-24398"
    },
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/commit/edbf6eea8e6c26a3937518d4ed91d8666edeec37"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/honojs/hono"
    },
    {
      "type": "WEB",
      "url": "https://github.com/honojs/hono/releases/tag/v4.11.7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Hono IPv4 address validation bypass in IP Restriction Middleware allows IP spoofing"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.