{
  "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": "0"
            },
            {
              "fixed": "4.1.136.Final"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-400"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-24T16:53:04Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\nAn attacker can cause Denial of Service by sending a specially crafted malicious XML payload (e.g., repeated `\u003c/` characters) to a Netty server utilizing XmlFrameDecoder, causing the server\u0027s EventLoop thread to exhaust CPU resources and become unresponsive.\n\n### Details\n`io.netty.handler.codec.xml.XmlFrameDecoder` suffers from a vulnerability resulting in CPU exhaustion. When `\u003c` followed by `/` is encountered, the decoder scans the remaining buffer for a closing `\u003e`.\nBecause the parser state is not saved between `decode()` invocations, an attacker can trickle-feed a payload of `\u003c/` characters. This forces the decoder to repeatedly rescan the entire accumulated buffer. A 1MB `maxFrameLength` is enough to completely hang a server\u0027s thread while it loops endlessly.\n\n### Impact\nDenial of Service via CPU Exhaustion. Any application utilizing Netty\u0027s XmlFrameDecoder is impacted. An unauthenticated remote attacker can exploit this flaw by sending a modest amount of malformed XML data to an exposed port.",
  "id": "GHSA-v74w-7mr3-4qg3",
  "modified": "2026-07-24T16:53:04Z",
  "published": "2026-07-24T16:53:04Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/security/advisories/GHSA-v74w-7mr3-4qg3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/pull/17063"
    },
    {
      "type": "WEB",
      "url": "https://github.com/netty/netty/pull/17065"
    },
    {
      "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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Netty: Denial of Service in XmlFrameDecoder via CPU Exhaustion"
}