{
  "id": "CVE-2026-42772",
  "url": "https://spydr.io/cve/CVE-2026-42772",
  "published": "2026-09-29T16:17:07.640Z",
  "modified": "2026-09-30T21:17:10.803Z",
  "score": 5.3,
  "severity": "medium",
  "cvss_version": "3.1",
  "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
  "score_source": "CISA ADP",
  "epss": 0.0033,
  "epss_percentile": 0.23817,
  "exploited": false,
  "kev": null,
  "ssvc_exploitation": "none",
  "vendors": [
    "OpenSSL"
  ],
  "products": [
    "OpenSSL"
  ],
  "cwes": [
    "CWE-407"
  ],
  "description": "Issue summary: The QUIC stream reassembly algorithm performance deteriorates progressively as packets are arriving out of order. The worst case has a quadratic complexity proportional to the number of stream frames kept in the buffer for the received stream data. Impact summary: A remote QUIC peer that completes the handshake can create a connection-scoped CPU pressure and potentially a Denial of Service using compliant STREAM frames inside the advertised receive window, with low attacker bandwidth. CWE: CWE-407: Inefficient Algorithmic Complexity Description: OpenSSL manages received QUIC stream fragments using a doubly-linked list. While it optimizes for append operations (at the end of the list), it falls back to a head-to-tail linear search for any fragment that does not immediately follow the current `tail`. By manipulating the sequence of offsets, an attacker can force the server to perform O(n^2) operations, consuming excessive CPU time for the QUIC process. FIPS impact: no The FIPS module is not affected as the QUIC implementation is outside of the OpenSSL FIPS module boundary.",
  "status": "Awaiting Analysis",
  "score_type": "Secondary",
  "scores": {
    "cvss_v40": null,
    "cvss_v31": 5.3,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://github.com/openssl/openssl/commit/32d0ed8afe1b8c3e7ece725b44663da3d7087a09",
      "tags": []
    },
    {
      "url": "https://github.com/openssl/openssl/commit/ca8402e273af4de5b3f04fa61a0f0c02ce3ae20e",
      "tags": []
    },
    {
      "url": "https://github.com/openssl/openssl/commit/eb2becc0a4baea7f3050a247834d0e5c2ebe1773",
      "tags": []
    },
    {
      "url": "https://github.com/openssl/openssl/commit/f42ae513bbda513b3c121d54834040ee4a0eae1a",
      "tags": []
    },
    {
      "url": "https://openssl-library.org/news/secadv/20260929.txt",
      "tags": []
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42772",
  "covered_in": [],
  "attribution": [
    {
      "source": "NVD",
      "url": "https://nvd.nist.gov",
      "notice": "This product uses data from the NVD API but is not endorsed or certified by the NVD."
    },
    {
      "source": "CISA KEV",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "notice": "Known exploited vulnerabilities from the CISA KEV catalog."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss",
      "notice": "Exploit prediction scores from FIRST EPSS."
    }
  ]
}