Critical

Security advisory

Type: advisorySources: OSVCVE: CVE-2019-14842

Structured reply is a feature of the newstyle NBD protocol allowing the server to send a reply in chunks. A bounds check which was supposed to test for chunk offsets smaller than the beginning of the request did not work because of signed/unsigned confusion. If one of these chunks contains a negative offset then data under control of the server is written to memory before the read buffer supplied by the client. If the read buffer is located on the stack then this allows the stack return address from nbd_pread() to be trivially modified, allowing arbitrary code execution under the control of the server. If the buffer is located on the heap then other memory objects before the buffer can be overwritten, which again would usually lead to arbitrary code execution.

Products: Not specified
Affected versions: Not specified
Fixed versions: Not specified
CVEs: CVE-2019-14842
Confirmed fixed CVEs: Not specified
Updated in this feed: 1 Nov 2026, 07:14 UTC · Revision 1

Source evidence

CVE-2019-14842

core-osv · Original source

Published 26 Nov 2019, 16:15 UTC

osv:CVE-2019-14842

Complete source record

{
  "id": "448e4248626e088ca858d543580d124a26a146be225d8731d9b91ecbe858102b",
  "url": "https://osv.dev/vulnerability/CVE-2019-14842",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2019-14842",
    "summary": "Structured reply is a feature of the newstyle NBD protocol allowing the server to send a reply in chunks. A bounds check which was supposed to test for chunk offsets smaller than the beginning of the request did not work because of signed/unsigned confusion. If one of these chunks contains a negative offset then data under control of the server is written to memory before the read buffer supplied by the client. If the read buffer is located on the stack then this allows the stack return address from nbd_pread() to be trivially modified, allowing arbitrary code execution under the control of the server. If the buffer is located on the heap then other memory objects before the buffer can be overwritten, which again would usually lead to arbitrary code execution.",
    "evidence": "osv:CVE-2019-14842",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2019-14842",
      "aliases": [
        "CVE-2019-14842"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/libguestfs/libnbd",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5dcf6e1a9e6b81b14be49c27ee29abd62f3c159d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:redhat:libnbd:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.0.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.0.2",
            "v1.0.1",
            "v1.0.0",
            "v0.9.9",
            "v0.9.8",
            "v0.9.7",
            "v0.9.6",
            "v0.1.9",
            "v0.1.8",
            "v0.1.7",
            "v0.1.6",
            "v0.1.5",
            "v0.1.4",
            "v0.1.3",
            "v0.1.2",
            "v0.1.1",
            "v0.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-14842.json"
          }
        },
        {
          "ranges": [
            {
              "repo": "https://gitlab.com/nbdkit/libnbd",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "5dcf6e1a9e6b81b14be49c27ee29abd62f3c159d"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:redhat:libnbd:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.0.3"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.0.2",
            "v1.0.1",
            "v1.0.0",
            "v0.9.9",
            "v0.9.8",
            "v0.9.7",
            "v0.9.6",
            "v0.1.9",
            "v0.1.8",
            "v0.1.7",
            "v0.1.6",
            "v0.1.5",
            "v0.1.4",
            "v0.1.3",
            "v0.1.2",
            "v0.1.1",
            "v0.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-14842.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:50.589249452Z",
      "provider": "osv",
      "references": [
        "https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2019-14842",
        "https://www.redhat.com/archives/libguestfs/2019-October/msg00060.html"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2019-14842",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 437281,
  "published_at": "2019-11-26T16:15:11.963+00:00"
}