{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/@fastify/reply-from",
          "product": "@fastify/reply-from",
          "vendor": "@fastify/reply-from",
          "versions": [
            {
              "lessThan": "12.6.2",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "12.6.2",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "packageURL": "pkg:npm/@fastify/http-proxy",
          "product": "@fastify/http-proxy",
          "vendor": "@fastify/reply-from",
          "versions": [
            {
              "lessThan": "11.4.4",
              "status": "affected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "11.4.4",
              "versionType": "semver"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "reporter",
          "value": "FredKSchott"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "mcollina"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "UlisesGascon"
        },
        {
          "lang": "en",
          "type": "remediation reviewer",
          "value": "climba03003"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "@fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client\u0027s Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests by listing them in the Connection header value. Any header added by the proxy for routing, access control, or security purposes can be selectively removed by a client. @fastify/http-proxy is also affected as it delegates to @fastify/reply-from. \n\nUpgrade to @fastify/reply-from v12.6.2 or @fastify/http-proxy v11.4.4 or later."
            }
          ],
          "value": "@fastify/reply-from v12.6.1 and earlier and @fastify/http-proxy v11.4.3 and earlier process the client\u0027s Connection header after the proxy has added its own headers via rewriteRequestHeaders. This allows attackers to retroactively strip proxy-added headers from upstream requests by listing them in the Connection header value. Any header added by the proxy for routing, access control, or security purposes can be selectively removed by a client. @fastify/http-proxy is also affected as it delegates to @fastify/reply-from. \n\nUpgrade to @fastify/reply-from v12.6.2 or @fastify/http-proxy v11.4.4 or later."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "baseScore": 9,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:L/SI:H/SA:N",
            "version": "4.0"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-644",
              "description": "CWE-644: Improper Neutralization of HTTP Headers for Scripting Syntax",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-15T10:13:25.147Z",
        "orgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
        "shortName": "openjs"
      },
      "references": [
        {
          "url": "https://github.com/fastify/fastify-reply-from/security/advisories/GHSA-gwhp-pf74-vj37"
        },
        {
          "url": "https://cna.openjsf.org/security-advisories.html"
        }
      ],
      "title": "@fastify/reply-from vulnerable to connection header abuse enabling stripping of proxy-added headers",
      "x_generator": {
        "engine": "cve-kit 1.0.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "ce714d77-add3-4f53-aff5-83d477b104bb",
    "assignerShortName": "openjs",
    "cveId": "CVE-2026-33805",
    "datePublished": "2026-04-15T10:13:25.147Z",
    "dateReserved": "2026-03-23T19:48:48.714Z",
    "dateUpdated": "2026-04-15T10:13:25.147Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}