Hex writes unverified package tarballs to standard output in mix hex.package fetch

{
  "id": "6a709fcb3e5d3a7155a5243220f152a96e49d9dbb86086f97338f228ed9dbfe6",
  "url": "https://osv.dev/vulnerability/CVE-2026-105280",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Hex writes unverified package tarballs to standard output in mix hex.package fetch",
    "summary": "Improper Validation of Integrity Check Value vulnerability in hexpm hex allows a package mirror to substitute the tarball that mix hex.package fetch PACKAGE VERSION --output - writes to standard output. Hex compares a fetched tarball's inner and outer checksums with the repository's signed registry before writing it to a file or unpacking it. The standard output branch of mix hex.package fetch writes the bytes returned by Hex.SCM.fetch/3 without that comparison, and Hex.SCM.fetch/3 doesn't verify freshly downloaded tarballs itself. When a mirror configured with HEX_MIRROR_URL or mirror_url serves altered bytes, the command prints them and exits successfully, while the same fetch with --output FILE fails with a checksum mismatch. Hex also prints diagnostics to standard output while the command runs: the body of a failed HTTP response from the update check or a registry fetch, and API warnings from the x-hex-message header. A mirror that answers one of those requests with an error whose body is a tar archive gets that archive written to standard output ahead of the verified tarball, so a pipeline that unpacks standard output extracts the mirror's files. This happens even when the checksum check then fails, because the archive is already on standard output. This issue affects hex: from 0.20.2 before 2.5.2.",
    "evidence": "osv:CVE-2026-105280",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-105280",
      "aliases": [
        "CVE-2026-105280",
        "EEF-CVE-2026-105280",
        "GHSA-98jr-23pm-vj7c"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/hexpm/hex",
              "type": "GIT",
              "events": [
                {
                  "introduced": "d1f5a085d9d4748e1f7d195e4bc39ebd77c28d9c"
                },
                {
                  "fixed": "8a14632ca6ba8a8afd2a3f2098bc267c13e13d93"
                },
                {
                  "introduced": "cd5040bf6ed18092885d14b28af9fec6a4d09eea"
                },
                {
                  "fixed": "c364cde2c8a753aca0bd7daab6e0079b30c3bc30"
                },
                {
                  "fixed": "d1f5a085d9d4748e1f7d195e4bc39ebd77c28d9c"
                },
                {
                  "fixed": "69489f8b74213f03db10169e6e5407e6d5fee512"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "d1f5a085d9d4748e1f7d195e4bc39ebd77c28d9c"
                      },
                      {
                        "fixed": "8a14632ca6ba8a8afd2a3f2098bc267c13e13d93"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "ChangesAt"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0.20.2"
                      },
                      {
                        "fixed": "2.5.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "d1f5a085d9d4748e1f7d195e4bc39ebd77c28d9c"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8a14632ca6ba8a8afd2a3f2098bc267c13e13d93"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "69489f8b74213f03db10169e6e5407e6d5fee512"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.5.1",
            "v2.5.0",
            "v2.2.2",
            "v2.4.2",
            "v2.4.1",
            "v2.4.0",
            "v2.2.1",
            "v2.2.0",
            "v2.0.6",
            "v2.1.1",
            "v0.21.3",
            "v2.1.0",
            "v2.0.5",
            "v2.0.4",
            "v2.0.3",
            "v2.0.2",
            "v2.0.1",
            "v2.0.0",
            "v1.0.1",
            "v1.0.0",
            "v0.21.2",
            "v0.21.1",
            "v0.21.0",
            "v0.20.5",
            "v0.20.4",
            "v0.20.3",
            "v0.20.2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-105280.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:53.172906108Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-105280.html",
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-105280",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105280.json",
        "https://github.com/hexpm/hex/security/advisories/GHSA-98jr-23pm-vj7c",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-105280",
        "https://github.com/hexpm/hex/commit/69489f8b74213f03db10169e6e5407e6d5fee512",
        "https://github.com/hexpm/hex/commit/8a14632ca6ba8a8afd2a3f2098bc267c13e13d93",
        "https://github.com/hexpm/hex/commit/d1f5a085d9d4748e1f7d195e4bc39ebd77c28d9c",
        "https://github.com/hexpm/hex"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-354"
        ],
        "cna_assigner": "EEF",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105280.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-105280",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 522263,
  "published_at": "2026-10-12T15:30:14.126+00:00"
}