CVE-2026-16728: Undici Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8xcm-r25x-g524",
  "modified" : "2026-08-03T19:24:33Z",
  "published" : "2026-08-03T19:24:33Z",
  "aliases" : [ "CVE-2026-16728" ],
  "summary" : "undici vulnerable to downstream response desynchronization via retry interceptor",
  "details" : "### Impact\n\nUndici's `interceptors.retry()` can deliver a response whose body length does not match the `Content-Length` header exposed to the application after a retry or resume of a partial response. Applications that use `interceptors.retry()` and forward upstream response headers and bodies downstream, for example proxy or gateway applications, may emit an invalid HTTP response with a stale `Content-Length` header. This can lead to downstream response desynchronization, connection hangs, or response corruption in clients or intermediaries that rely on the forwarded framing metadata.\n\nA malicious or faulty upstream can respond to a range request with a `206 Partial Content` response such as:\n\n```http\nContent-Range: bytes 0-99/300\nContent-Length: 300\n```\n\nand then send only 99 bytes before closing the socket. `interceptors.retry()` can then retry with `Range: bytes=99-99`, receive the final byte, and deliver a 100-byte body to the application while the response headers still contain `Content-Length: 300` from the first response.\n\nThe bug requires `interceptors.retry()` to be enabled, an upstream that returns a partial response with a mismatched framing header, and a downstream forwarder that does not remove or recalculate `Content-Length`.\n\n### Patches\n\nPatched in undici v6.28.0, v7.29.0, and v8.9.0. Users should upgrade to one of these versions or later.\n\n### Workarounds\n\n- Disable `interceptors.retry()` for untrusted upstreams.\n- Remove or recalculate `Content-Length` before forwarding a response body assembled or transformed by Undici.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "undici"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "6.28.0"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "undici"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "7.0.0"
      }, {
        "fixed" : "7.29.0"
      } ]
    } ]
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "undici"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "8.0.0"
      }, {
        "fixed" : "8.9.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/security/advisories/GHSA-8xcm-r25x-g524"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-16728"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/commit/1b5a5312c3a7d7a30c31bf0d000b39a8a2531e1c"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/commit/2b3f749336d356bbbc50192f87f6cf7bc714721a"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/commit/4a9dafb16ff43880cf590e6d9c2aeee25fbff6d7"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/commit/4fd5a0c61e627f928b7003adc4ffe1e55ec63420"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/commit/cba3a52ac2e7abcc4e656d82af8579ea82c2bb9e"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/commit/e11a68ed4ff345c79402476f7a00d473443e318d"
  }, {
    "type" : "WEB",
    "url" : "https://hackerone.com/reports/3828685"
  }, {
    "type" : "WEB",
    "url" : "https://cna.openjsf.org/security-advisories.html"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/nodejs/undici"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/releases/tag/v6.28.0"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/releases/tag/v7.29.0"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/nodejs/undici/releases/tag/v8.9.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-444" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-03T19:24:33Z",
    "nvd_published_at" : "2026-07-29T21:17:46Z"
  }
}