Infinite loop in HTTP/2 transport when given bad SETTINGS_MAX_FRAME_SIZE in net/http/internal/http2 in golang.org/x/net

{
  "id": "debffe9cccae972a324ad86e2c41b280e6bd94353f365a69379ad227238fe91f",
  "url": "https://osv.dev/vulnerability/GO-2026-4918",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Infinite loop in HTTP/2 transport when given bad SETTINGS_MAX_FRAME_SIZE in net/http/internal/http2 in golang.org/x/net",
    "summary": "When processing HTTP/2 SETTINGS frames, transport will enter an infinite loop of writing CONTINUATION frames if it receives a SETTINGS_MAX_FRAME_SIZE with a value of 0.",
    "evidence": "osv:GO-2026-4918",
    "products": [
      {
        "name": {
          "value": "golang.org/x/net",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.53.0",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "stdlib",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.25.10",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "1.26.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "GO-2026-4918",
      "aliases": [
        "BIT-golang-2026-33814",
        "CVE-2026-33814",
        "GO-2026-4918"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.53.0"
                }
              ]
            }
          ],
          "package": {
            "name": "golang.org/x/net",
            "purl": "pkg:golang/golang.org/x/net",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://vuln.go.dev/ID/GO-2026-4918.json"
          },
          "ecosystem_specific": {
            "imports": [
              {
                "path": "golang.org/x/net/http2",
                "symbols": [
                  "Transport.NewClientConn",
                  "Transport.RoundTrip",
                  "Transport.RoundTripOpt",
                  "clientConnPool.GetClientConn",
                  "clientConnReadLoop.processSettingsNoWrite",
                  "noDialClientConnPool.GetClientConn",
                  "noDialH2RoundTripper.NewClientConn",
                  "noDialH2RoundTripper.RoundTrip",
                  "unencryptedTransport.RoundTrip"
                ]
              }
            ]
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "1.25.10"
                },
                {
                  "introduced": "1.26.0-0"
                },
                {
                  "fixed": "1.26.3"
                }
              ]
            }
          ],
          "package": {
            "name": "stdlib",
            "purl": "pkg:golang/stdlib",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://vuln.go.dev/ID/GO-2026-4918.json"
          },
          "ecosystem_specific": {
            "imports": [
              {
                "path": "net/http",
                "symbols": [
                  "Client.CloseIdleConnections",
                  "Client.Do",
                  "Client.Get",
                  "Client.Head",
                  "Client.Post",
                  "Client.PostForm",
                  "ClientConn.Close",
                  "ClientConn.RoundTrip",
                  "Get",
                  "Head",
                  "Post",
                  "PostForm",
                  "Transport.CloseIdleConnections",
                  "Transport.NewClientConn",
                  "Transport.RoundTrip",
                  "http1ClientConn.Close",
                  "http1ClientConn.RoundTrip",
                  "http2Transport.NewClientConn",
                  "http2Transport.RoundTrip",
                  "http2Transport.RoundTripOpt",
                  "http2clientConnPool.GetClientConn",
                  "http2clientConnReadLoop.processSettingsNoWrite",
                  "http2noDialClientConnPool.GetClientConn",
                  "http2noDialH2RoundTripper.NewClientConn",
                  "http2noDialH2RoundTripper.RoundTrip",
                  "http2unencryptedTransport.RoundTrip"
                ]
              }
            ]
          }
        }
      ],
      "modified": "2026-10-16T10:42:05.228443950Z",
      "provider": "osv",
      "references": [
        "https://go.dev/cl/761581",
        "https://go.dev/cl/761640",
        "https://go.dev/issue/78476",
        "https://groups.google.com/g/golang-announce/c/qcCIEXso47M"
      ],
      "provider_metadata": {
        "url": "https://pkg.go.dev/vuln/GO-2026-4918",
        "review_status": "REVIEWED"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-33814",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 340598,
  "published_at": "2026-05-07T19:21:40+00:00"
}