Limit handshake messages we are willing to accept post-handshake in crypto/tls

{
  "id": "24a83a0e7122b17937efbadc4b1ffdf5a0f64fd16b079e69f1664bdd6d0a153d",
  "url": "https://osv.dev/vulnerability/GO-2026-6090",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Limit handshake messages we are willing to accept post-handshake in crypto/tls",
    "summary": "Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely.",
    "evidence": "osv:GO-2026-6090",
    "products": [
      {
        "name": {
          "value": "stdlib",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.25.13",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.26.6",
            "evidence": "/affected/0/ranges"
          },
          {
            "value": "1.27.0-rc.3",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "GO-2026-6090",
      "aliases": [
        "BIT-golang-2026-56862",
        "CVE-2026-56862",
        "GO-2026-6090"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.25.13"
                },
                {
                  "introduced": "1.26.0-0"
                },
                {
                  "fixed": "1.26.6"
                },
                {
                  "introduced": "1.27.0-0"
                },
                {
                  "fixed": "1.27.0-rc.3"
                }
              ]
            }
          ],
          "package": {
            "name": "stdlib",
            "purl": "pkg:golang/stdlib",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://vuln.go.dev/ID/GO-2026-6090.json"
          },
          "ecosystem_specific": {
            "imports": [
              {
                "path": "crypto/tls",
                "symbols": [
                  "Conn.Handshake",
                  "Conn.HandshakeContext",
                  "Conn.Read",
                  "Conn.Write",
                  "Conn.readRecordOrCCS",
                  "Dial",
                  "DialWithDialer",
                  "Dialer.Dial",
                  "Dialer.DialContext",
                  "QUICConn.HandleData",
                  "QUICConn.Start"
                ]
              }
            ]
          }
        }
      ],
      "modified": "2026-10-20T10:42:24.559672268Z",
      "provider": "osv",
      "references": [
        "https://go.dev/issue/80528",
        "https://go.dev/cl/804261",
        "https://groups.google.com/g/golang-announce/c/94pEornpRlI"
      ],
      "provider_metadata": {
        "url": "https://pkg.go.dev/vuln/GO-2026-6090",
        "review_status": "REVIEWED"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-56862",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 379199,
  "published_at": "2026-08-13T21:43:54+00:00"
}