{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": [
              "cpe:2.3:a:twisted:twisted:*:*:*:*:*:*:*:*",
              "cpe:2.3:a:twisted:twisted:26.4.0:rc1:*:*:*:*:*:*"
            ],
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "26.4.0"
              },
              {
                "introduced": "26.4.0-rc1"
              },
              {
                "last_affected": "26.4.0-rc1"
              }
            ],
            "source": [
              "CPE_RANGE",
              "CPE_STRING"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3dc92b79333c231338390c2b8cec5c142a31863d"
            },
            {
              "introduced": "819185e068aab1f9b0f9a2a5e08aa942038733d9"
            }
          ],
          "repo": "https://github.com/twisted/twisted",
          "type": "GIT"
        }
      ],
      "versions": [
        "26.4.0-rc1"
      ]
    }
  ],
  "aliases": [
    "GHSA-grgv-6hw6-v9g4"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-400",
      "CWE-407"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42304.json"
  },
  "details": "Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.4.0rc2, the twisted.names module is vulnerable to a Denial of Service (DoS) attack via resource exhaustion during DNS name decompression. A remote, unauthenticated attacker can exploit this by sending a crafted TCP DNS packet containing deeply chained compression pointers. This flaw bypasses previous loop-prevention logic, causing the single-threaded Twisted reactor to hang while processing millions of recursive lookups, effectively freezing the server. This vulnerability is fixed in 26.4.0rc2.",
  "id": "CVE-2026-42304",
  "modified": "2026-07-08T05:36:54.009162689Z",
  "published": "2026-05-13T20:20:29.149Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42304.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/twisted/twisted/security/advisories/GHSA-grgv-6hw6-v9g4"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42304"
    }
  ],
  "schema_version": "1.7.5",
  "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": "Twisted: Denial of Service (DoS) in twisted.names via Crafted DNS Compression Pointer Chains"
}