{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:tinyproxy_project:tinyproxy:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "last_affected": "1.11.3"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "CPE_RANGE"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "baecbf4c3e006fa68ab92f65bbd4138c47ede111"
            }
          ],
          "repo": "https://github.com/tinyproxy/tinyproxy",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "TuranSec",
    "cwe_ids": [
      "CWE-444"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31842.json"
  },
  "details": "Tinyproxy through 1.11.3 is vulnerable to HTTP request parsing desynchronization due to a case-sensitive comparison of the Transfer-Encoding header in src/reqs.c. The is_chunked_transfer() function uses strcmp() to compare the header value against \"chunked\", even though RFC 7230 specifies that transfer-coding names are case-insensitive. By sending a request with Transfer-Encoding: Chunked, an unauthenticated remote attacker can cause Tinyproxy to misinterpret the request as having no body. In this state, Tinyproxy sets content_length.client to -1, skips pull_client_data_chunked(), forwards request headers upstream, and transitions into relay_connection() raw TCP forwarding while unread body data remains buffered. This leads to inconsistent request state between Tinyproxy and backend servers. RFC-compliant backends (e.g., Node.js, Nginx) will continue waiting for chunked body data, causing connections to hang indefinitely. This behavior enables application-level denial of service through backend worker exhaustion. Additionally, in deployments where Tinyproxy is used for request-body inspection, filtering, or security enforcement, the unread body may be forwarded without proper inspection, resulting in potential security control bypass.",
  "id": "CVE-2026-31842",
  "modified": "2026-07-15T01:49:06.014188202Z",
  "published": "2026-04-07T11:17:33.621Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31842.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31842"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/tinyproxy/tinyproxy/issues/604"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/tinyproxy/tinyproxy"
    },
    {
      "type": "ARTICLE",
      "url": "https://datatracker.ietf.org/doc/html/rfc7230"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Tinyproxy HTTP request parsing desynchronization via case-sensitive Transfer-Encoding handling"
}