{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "4.0.0"
              },
              {
                "fixed": "4.0.2"
              },
              {
                "introduced": "3.6.0"
              },
              {
                "fixed": "3.6.4"
              },
              {
                "introduced": "3.5.0"
              },
              {
                "fixed": "3.5.8"
              },
              {
                "introduced": "3.4.0"
              },
              {
                "fixed": "3.4.7"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "11b7b6ea3b65a584e1d31408ed1bdb139465cffd"
            },
            {
              "introduced": "7b371d80d959ec9ab4139d09d78e83c090de9779"
            },
            {
              "introduced": "636dfadc70ce26f2473870570bfd9ec352806b1d"
            },
            {
              "introduced": "98acb6b02839c609ef5b837794e08d906d965335"
            },
            {
              "fixed": "f089acdf4bc7ba94a79f4bf6eb7362c3e7d14aa9"
            },
            {
              "fixed": "d3c1b1169b3569ff3069e5b399f47b2b28e03d79"
            },
            {
              "fixed": "f4dc4d58b48d346a8270183f89acf826d459b0ca"
            },
            {
              "fixed": "0c5d912057abf47505b4ad455da49fbab99b76f1"
            },
            {
              "fixed": "7308946576b12e64b8be53bcf0a120354b2b42bc"
            },
            {
              "fixed": "7c98d79738549df92868e7dd9be4bbf061eed709"
            },
            {
              "fixed": "bf84721c2548351176e367e6de505792f0118dc6"
            },
            {
              "fixed": "c902e5f16d6a9e130e96d3ca6d8f64d71652e393"
            }
          ],
          "repo": "https://github.com/openssl/openssl",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "openssl",
    "cwe_ids": [
      "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63075.json"
  },
  "details": "Issue summary: When OpenSSL processes QUIC traffic from a peer that repeatedly\nsends ack-eliciting packets while not acknowledging ACK-only responses, the\nQUIC stack can retain ACK-only packet metadata for the lifetime of the\nconnection.\n\nImpact summary: A remote peer that can complete a QUIC handshake can\ncause connection-scoped memory growth which may lead to Denial of Service\nthrough memory exhaustion, especially with sustained traffic or many concurrent\nQUIC connections.\n\nCWE: CWE-770: Allocation of Resources Without Limits or Throttling\n\nDescription: When the OpenSSL QUIC stack sends an ACK-only packet,\nthere is no requirement by the QUIC protocol that the peer will acknowledge\nthat ACK-only packet (i.e. it is itself not ack-eliciting). However, the OpenSSL\nimplementation stores the metadata about the ACK frames regardless.\nIn and of itself that's ok, but if a malicious peer establishes a connection, and\nthen drives the connection such that ACK-only packets are forced from the \nOpenSSL implementation peer (i.e., by sending numerous PING frames),\nand then withholding any subsequent acks for ack-eliciting data, like\nlegitimate data, said malicious peer can force inappropriate memory growth\non the OpenSSL peer, potentially leading to a Denial of Service.\n\nThe fix is to ensure that we account for the transmission of the ACK-only\npacket in the packet histories high and low watermark without actually storing\nthe ACK-only packet metadata itself.\n\nFIPS impact: no\nThe OpenSSL FIPS module is not affected as the QUIC code is\noutside the FIPS module boundary.",
  "id": "CVE-2026-63075",
  "modified": "2026-08-30T03:30:26.537520862Z",
  "published": "2026-08-25T13:00:04.752Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/63xxx/CVE-2026-63075.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-63075"
    },
    {
      "type": "ADVISORY",
      "url": "https://openssl-library.org/news/secadv/20260825.txt"
    },
    {
      "type": "FIX",
      "url": "https://github.com/openssl/openssl/commit/7308946576b12e64b8be53bcf0a120354b2b42bc"
    },
    {
      "type": "FIX",
      "url": "https://github.com/openssl/openssl/commit/7c98d79738549df92868e7dd9be4bbf061eed709"
    },
    {
      "type": "FIX",
      "url": "https://github.com/openssl/openssl/commit/bf84721c2548351176e367e6de505792f0118dc6"
    },
    {
      "type": "FIX",
      "url": "https://github.com/openssl/openssl/commit/c902e5f16d6a9e130e96d3ca6d8f64d71652e393"
    }
  ],
  "schema_version": "1.9.0",
  "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": "QUIC ACK-only Packet Retention Can Cause Memory Exhaustion"
}