GHSA-4QHR-G3C6-FCFX

Vulnerability from github – Published: 2026-07-22 21:43 – Updated: 2026-07-22 21:43
VLAI
Summary
Netty XML: Injection / Risky Sink — unconfigured XML factory with active DTD and entity handling
Details

Any caller that can deliver bytes to a Netty channel pipeline containing XmlDecoder can send XML with a DOCTYPE declaration to a parser instantiated with no security configuration — but whether external entities are actually resolved depends on Aalto XML's async parser behavior, making this a confirmed misconfiguration with conditional exploitability.

Severity
8.3 (High)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.2.15.Final"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "io.netty:netty-codec-xml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.2.0.Final"
            },
            {
              "fixed": "4.2.16.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.1.135.Final"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "io.netty:netty-codec-xml"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.1.0.Final"
            },
            {
              "fixed": "4.1.136.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-56817"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-611"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-22T21:43:16Z",
    "nvd_published_at": "2026-07-21T23:17:52Z",
    "severity": "HIGH"
  },
  "details": "Any caller that can deliver bytes to a Netty channel pipeline containing `XmlDecoder` can send XML with a DOCTYPE declaration to a parser instantiated with no security configuration \u2014 but whether external entities are actually resolved depends on Aalto XML\u0027s async parser behavior, making this a confirmed misconfiguration with conditional exploitability.",
  "id": "GHSA-4qhr-g3c6-fcfx",
  "modified": "2026-07-22T21:43:17Z",
  "published": "2026-07-22T21:43:16Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/security/advisories/GHSA-4qhr-g3c6-fcfx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56817"
    },
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/commit/5b68c61f37aa4a3045cba624cbea239655c9003b"
    },
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/commit/bb2ff68a1fb71cb4b0eb9a9e17b66c52aff680c6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/netty/netty"
    },
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/releases/tag/netty-4.1.136.Final"
    },
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/releases/tag/netty-4.2.16.Final"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Netty XML: Injection / Risky Sink \u2014 unconfigured XML factory with active DTD and entity handling"
}



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Nomenclature

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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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