{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "OpenSSL",
          "vendor": "OpenSSL",
          "versions": [
            {
              "lessThan": "4.0.3",
              "status": "affected",
              "version": "4.0.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.6.5",
              "status": "affected",
              "version": "3.6.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.5.9",
              "status": "affected",
              "version": "3.5.0",
              "versionType": "semver"
            },
            {
              "lessThan": "3.4.8",
              "status": "affected",
              "version": "3.4.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "Bhabani Sankar Das"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Alexandr Nedvedicky"
        }
      ],
      "datePublic": "2026-09-29T16:21:57+02:00",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "Issue summary: A malicious remote peer may flood the local QUIC<br>stack with NEW_CONNECTION_ID frames by avoiding a limit check on<br>how many connection IDs the remote QUIC stack can use.<br><br>Impact summary: The local QUIC stack sends a RETIRE_CONN_ID frame<br>for every NEW_CONNECTION_ID frame it receives. The RETIRE_CONN_ID<br>frame is dispatched via the Control Frame Queue (CFQ). If the remote<br>peer also withholds ACKs, then it can force the local stack<br>to allocate ~400MB (depending on ACK delay).<br><br>CWE: CWE-770: Allocation of Resources Without Limits or Throttling<br><br>Description: RFC 9000 sections 5.1.1 and 5.1.2 [1] describe the mechanism<br>by which a remote peer can notify the local QUIC stack to change the<br>destination connection ID (a.k.a. CID) the local stack uses to<br>identify the connection at the remote peer. Each CID is associated<br>with a sequence number. The sequence number is transmitted<br>in NEW_CONNECTION_ID and RETIRE_CONNECTION_ID frames to identify the CID<br>which is being either associated with a connection or retired.<br><br>The remote peer sends a NEW_CONNECTION_ID frame to let the local stack know<br>a new CID is being associated with an existing connection. The<br>NEW_CONNECTION_ID frame carries the new CID, its sequence number, and the<br>retire-prior-to number. The retire-prior-to identifies existing<br>CIDs that are to be retired. The local QUIC stack must send a<br>RETIRE_CONNECTION_ID for every destination CID whose sequence number<br>is less than retire-prior-to. The CID becomes retired after the<br>local stack receives an ACK for its RETIRE_CONNECTION_ID frame.<br><br>Although the OpenSSL QUIC stack supports at most one destination CID<br>for every connection, it can be tricked into processing more than<br>one RETIRE_CONNECTION_ID frame per connection. The OpenSSL QUIC<br>stack currently retires the destination CID as soon as it receives<br>the NEW_CONNECTION_ID, while in fact the destination CID must<br>be retired after an ACK for the RETIRE_CONNECTION_ID frame is received.<br>Correcting the flawed logic also fixes the backlog growth.<br><br>[1] https://datatracker.ietf.org/doc/html/rfc9000#name-issuing-connection-ids<br><br>FIPS impact: no<br>The FIPS module is not affected as the QUIC implementation is outside of<br>the OpenSSL FIPS module boundary."
            }
          ],
          "value": "Issue summary: A malicious remote peer may flood the local QUIC\nstack with NEW_CONNECTION_ID frames by avoiding a limit check on\nhow many connection IDs the remote QUIC stack can use.\n\nImpact summary: The local QUIC stack sends a RETIRE_CONN_ID frame\nfor every NEW_CONNECTION_ID frame it receives. The RETIRE_CONN_ID\nframe is dispatched via the Control Frame Queue (CFQ). If the remote\npeer also withholds ACKs, then it can force the local stack\nto allocate ~400MB (depending on ACK delay).\n\nCWE: CWE-770: Allocation of Resources Without Limits or Throttling\n\nDescription: RFC 9000 sections 5.1.1 and 5.1.2 [1] describe the mechanism\nby which a remote peer can notify the local QUIC stack to change the\ndestination connection ID (a.k.a. CID) the local stack uses to\nidentify the connection at the remote peer. Each CID is associated\nwith a sequence number. The sequence number is transmitted\nin NEW_CONNECTION_ID and RETIRE_CONNECTION_ID frames to identify the CID\nwhich is being either associated with a connection or retired.\n\nThe remote peer sends a NEW_CONNECTION_ID frame to let the local stack know\na new CID is being associated with an existing connection. The\nNEW_CONNECTION_ID frame carries the new CID, its sequence number, and the\nretire-prior-to number. The retire-prior-to identifies existing\nCIDs that are to be retired. The local QUIC stack must send a\nRETIRE_CONNECTION_ID for every destination CID whose sequence number\nis less than retire-prior-to. The CID becomes retired after the\nlocal stack receives an ACK for its RETIRE_CONNECTION_ID frame.\n\nAlthough the OpenSSL QUIC stack supports at most one destination CID\nfor every connection, it can be tricked into processing more than\none RETIRE_CONNECTION_ID frame per connection. The OpenSSL QUIC\nstack currently retires the destination CID as soon as it receives\nthe NEW_CONNECTION_ID, while in fact the destination CID must\nbe retired after an ACK for the RETIRE_CONNECTION_ID frame is received.\nCorrecting the flawed logic also fixes the backlog growth.\n\n[1] https://datatracker.ietf.org/doc/html/rfc9000#name-issuing-connection-ids\n\nFIPS impact: no\nThe FIPS module is not affected as the QUIC implementation is outside of\nthe OpenSSL FIPS module boundary."
        }
      ],
      "metrics": [
        {
          "format": "other",
          "other": {
            "content": {
              "text": "Low"
            },
            "type": "https://openssl-library.org/policies/general/security-policy/"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "CWE-770 Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "orgId": "00000000-0000-4000-9000-000000000000",
        "shortName": "openssl"
      },
      "references": [
        {
          "name": "OpenSSL Advisory",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://openssl-library.org/news/secadv/20260929.txt"
        },
        {
          "name": "4.0.3 git commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/openssl/openssl/commit/e9e5155833fa968bee50024bf9ca3a185ab599fe"
        },
        {
          "name": "3.6.5 git commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/openssl/openssl/commit/4685c914b0d410b1034f40b547c95bc95e7a380a"
        },
        {
          "name": "3.5.9 git commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/openssl/openssl/commit/dba3c48d653c64fcbc9070a17a0ee2b3e2f3af1f"
        },
        {
          "name": "3.4.8 git commit",
          "tags": [
            "patch"
          ],
          "url": "https://github.com/openssl/openssl/commit/9a30fe0fba195c14e5b87bf93c0d0fdb70373806"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "QUIC: Unbounded RETIRE_CONNECTION_ID Backlog",
      "x_generator": {
        "engine": "Vulnogram 0.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "00000000-0000-4000-9000-000000000000",
    "cveId": "CVE-2026-84784",
    "requesterUserId": "00000000-0000-4000-9000-000000000000",
    "serial": 1,
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}