{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "2.6.2"
              },
              {
                "fixed": "2.8.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "83f8643ffb5b7f197457379148e2fa118ab0fcdc"
            },
            {
              "fixed": "ea2ad7b21a80da3632f80016526a18864586077f"
            },
            {
              "fixed": "b1d30ab61fe0db8f11092805e8c5ac43e091064a"
            }
          ],
          "repo": "https://github.com/urllib3/urllib3",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-gh4c-6fx4-qh6g"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-835"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97688.json"
  },
  "details": "urllib3 is an HTTP client library for Python. From 2.6.2 until 2.8.0, HTTPResponse.stream and HTTPResponse.read_chunked can enter an infinite loop because the Deflate decoder retains trailing bytes as unconsumed input after reaching end-of-stream and repeatedly decodes them without progress. The issue occurs when an untrusted server sends a chunked Deflate response whose decoded body exceeds a positive finite chunk size and whose encoded body has trailing bytes, specifically a response with Transfer-Encoding: chunked and Content-Encoding: deflate, content decoding enabled, and the positive finite amt=N streaming chunk size. The attack mechanism is that a malicious server returns a compressed chunked response with trailing bytes after the Deflate stream. The impact is excessive CPU usage and a request that does not complete, and network read timeouts do not interrupt the loop because no further socket read occurs. This issue is fixed in version 2.8.0.",
  "id": "CVE-2026-97688",
  "modified": "2026-10-02T03:30:47.242065245Z",
  "published": "2026-09-29T15:32:17.622Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/urllib3/urllib3/releases/tag/2.8.0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97688.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97688"
    },
    {
      "type": "FIX",
      "url": "https://github.com/urllib3/urllib3/commit/ea2ad7b21a80da3632f80016526a18864586077f"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "urllib3: Chunked Deflate streaming can enter an infinite loop"
}