erlang-hex — security advisory

{
  "id": "a91ba6c78c05c99f185d5c91e67555e494eccc73916a451463792d2acb5813d9",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-103503",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-103503",
    "summary": "Improper Certificate Validation vulnerability in hexpm hex allows an attacker who can intercept HTTPS connections, and holds a certificate for a Hex host issued by a CA in Hex's bundled CA store, to impersonate that host to users who set cacerts_path to a CA store that leaves that CA out. cacerts_path (HEX_CACERTS_PATH) is documented as the path to the CA certificate store, used instead of the CA bundle that ships with Hex. Hex.HTTP.SSL.ssl_opts/1 passes the configured store as the cacerts option, but builds the partial_chain callback from the bundled store whether cacerts_path is set or not. Hex.HTTP.SSL.partial_chain/2 accepts a server chain when any certificate in it has the same public key as a bundled CA certificate, so a chain that leads to a bundled CA passes verification although the configured store doesn't contain that CA. Hostname verification still applies. This issue affects hex: from 0.20.2 before 2.5.2.",
    "evidence": "osv:DEBIAN-CVE-2026-103503",
    "products": [
      {
        "name": {
          "value": "erlang-hex",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "2.0.6-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.4.2-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.4.2-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.5.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.5.1-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.5.3-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "2.5.3-2",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "erlang-hex",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.5.3-2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "2.0.6-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.4.2-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.4.2-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.5.1-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.5.1-2",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "2.5.3-1",
            "evidence": "/affected/1/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2026-103503",
      "aliases": [
        "DEBIAN-CVE-2026-103503"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:A/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "erlang-hex",
            "purl": "pkg:deb/debian/erlang-hex?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "2.0.6-2",
            "2.4.2-1",
            "2.4.2-2",
            "2.5.1-1",
            "2.5.1-2",
            "2.5.3-1",
            "2.5.3-2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-103503.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2.5.3-2"
                }
              ]
            }
          ],
          "package": {
            "name": "erlang-hex",
            "purl": "pkg:deb/debian/erlang-hex?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "2.0.6-2",
            "2.4.2-1",
            "2.4.2-2",
            "2.5.1-1",
            "2.5.1-2",
            "2.5.3-1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-103503.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-23T17:47:28.921953300Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-103503"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-103503"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-103503",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 417160,
  "published_at": "2026-10-12T16:17:02.427+00:00"
}