{
  "id": "nginx/upstream-sent-http-1-1-response-while-reading-response-header",
  "signature": "upstream sent HTTP/1.1 response while reading response header from upstream",
  "signature_zh": "上游发送了HTTP/1.1响应，而读取响应头时预期为HTTP/1.0",
  "regex": "upstream sent HTTP/1\\.[01] response while reading response header from upstream",
  "domain": "nginx",
  "category": "protocol_error",
  "subcategory": null,
  "root_cause": "Upstream server returns HTTP/1.1 response but Nginx is configured to expect HTTP/1.0, causing header parsing mismatch.",
  "root_cause_type": "generic",
  "root_cause_zh": "上游服务器返回HTTP/1.1响应，但Nginx配置为期望HTTP/1.0，导致头部解析不匹配。",
  "versions": [
    {
      "version": "nginx 1.20.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "nginx 1.22.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "nginx 1.24.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "Apache 2.4.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    },
    {
      "version": "Gunicorn 20.x",
      "introduced": null,
      "deprecated": null,
      "removed": null,
      "behavior_change": null,
      "status": "active"
    }
  ],
  "os_specific": {},
  "dead_ends": [
    {
      "action": "Disabling HTTP/1.1 support on upstream",
      "why_fails": "Upstream servers often default to HTTP/1.1; disabling may break functionality.",
      "fail_rate": 0.6,
      "condition": "",
      "sources": []
    },
    {
      "action": "Increasing proxy buffer sizes",
      "why_fails": "Buffer size does not affect protocol version negotiation.",
      "fail_rate": 0.8,
      "condition": "",
      "sources": []
    },
    {
      "action": "Adding proxy_set_header Host $host",
      "why_fails": "Header manipulation doesn't change protocol version.",
      "fail_rate": 0.9,
      "condition": "",
      "sources": []
    }
  ],
  "workarounds": [
    {
      "action": "Set proxy_http_version to 1.1 in the location block: proxy_http_version 1.1;",
      "success_rate": 0.85,
      "how": "Set proxy_http_version to 1.1 in the location block: proxy_http_version 1.1;",
      "condition": "",
      "sources": []
    },
    {
      "action": "Configure upstream to return HTTP/1.0 responses if possible.",
      "success_rate": 0.7,
      "how": "Configure upstream to return HTTP/1.0 responses if possible.",
      "condition": "",
      "sources": []
    }
  ],
  "workarounds_zh": [
    "在location块中设置proxy_http_version为1.1：proxy_http_version 1.1;",
    "如果可能，配置上游返回HTTP/1.0响应。"
  ],
  "transition_graph": {
    "leads_to": [],
    "preceded_by": [],
    "frequently_confused_with": []
  },
  "official_doc_url": "https://nginx.org/en/docs/http/ngx_http_upstream_module.html#proxy_http_version",
  "official_doc_section": null,
  "error_code": null,
  "verification_tier": "ai_generated",
  "confidence": 0.88,
  "fix_success_rate": 0.85,
  "resolvable": "true",
  "first_seen": "2023-11-15",
  "last_confirmed": "2024-06-01",
  "last_updated": "2024-06-01",
  "evidence_count": 1,
  "tags": [],
  "locale": "en",
  "aliases": []
}