{
  "id": "CVE-2026-63075",
  "url": "https://spydr.io/cve/CVE-2026-63075",
  "published": "2026-08-25T13:19:26.413Z",
  "modified": "2026-09-11T21:17:05.403Z",
  "score": 7.5,
  "severity": "high",
  "cvss_version": "3.1",
  "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
  "score_source": "CISA ADP",
  "epss": 0.00778,
  "epss_percentile": 0.54312,
  "exploited": false,
  "kev": null,
  "ssvc_exploitation": "none",
  "vendors": [
    "OpenSSL"
  ],
  "products": [
    "OpenSSL"
  ],
  "cwes": [
    "CWE-770"
  ],
  "description": "Issue summary: When OpenSSL processes QUIC traffic from a peer that repeatedly sends ack-eliciting packets while not acknowledging ACK-only responses, the QUIC stack can retain ACK-only packet metadata for the lifetime of the connection. Impact summary: A remote peer that can complete a QUIC handshake can cause connection-scoped memory growth which may lead to Denial of Service through memory exhaustion, especially with sustained traffic or many concurrent QUIC connections. CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: When the OpenSSL QUIC stack sends an ACK-only packet, there is no requirement by the QUIC protocol that the peer will acknowledge that ACK-only packet (i.e. it is itself not ack-eliciting). However, the OpenSSL implementation stores the metadata about the ACK frames regardless. In and of itself that's ok, but if a malicious peer establishes a connection, and then drives the connection such that ACK-only packets are forced from the OpenSSL implementation peer (i.e., by sending numerous PING frames), and then withholding any subsequent acks for ack-eliciting data, like legitimate data, said malicious peer can force inappropriate memory growth on the OpenSSL peer, potentially leading to a Denial of Service. The fix is to ensure that we account for the transmission of the ACK-only packet in the packet histories high and low watermark without actually storing the ACK-only packet metadata itself. FIPS impact: no The OpenSSL FIPS module is not affected as the QUIC code is outside the FIPS module boundary.",
  "status": "Analyzed",
  "score_type": "Secondary",
  "scores": {
    "cvss_v40": null,
    "cvss_v31": 7.5,
    "cvss_v30": null
  },
  "references": [
    {
      "url": "https://github.com/openssl/openssl/commit/7308946576b12e64b8be53bcf0a120354b2b42bc",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/openssl/openssl/commit/7c98d79738549df92868e7dd9be4bbf061eed709",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/openssl/openssl/commit/bf84721c2548351176e367e6de505792f0118dc6",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/openssl/openssl/commit/c902e5f16d6a9e130e96d3ca6d8f64d71652e393",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://openssl-library.org/news/secadv/20260825.txt",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ],
  "nvd_url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63075",
  "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."
    }
  ]
}