CVE-2026-103503

{
  "id": "CVE-2026-103503",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "published": "2026-10-12T16:17:02.427",
  "lastModified": "2026-11-11T15:17:12.590",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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.\n\ncacerts_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.\n\nThis issue affects hex: from 0.20.2 before 2.5.2."
    }
  ],
  "affected": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "affectedData": [
        {
          "vendor": "hexpm",
          "product": "hex",
          "defaultStatus": "unaffected",
          "packageName": "hex",
          "cpes": [
            "cpe:2.3:a:hexpm:hex:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "'Elixir.Hex.HTTP.SSL'"
          ],
          "programFiles": [
            "lib/hex/http/ssl.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.Hex.HTTP.SSL':ssl_opts/1"
            },
            {
              "name": "'Elixir.Hex.HTTP.SSL':partial_chain/2"
            }
          ],
          "repo": "https://github.com/hexpm/hex",
          "packageURL": "pkg:otp/hex?repository_url=https:%2F%2Fgithub.com%2Fhexpm%2Fhex&vcs_url=git%2Bhttps:%2F%2Fgithub.com%2Fhexpm%2Fhex.git",
          "versions": [
            {
              "version": "0.20.2",
              "lessThan": "2.5.2",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "hexpm",
          "product": "hex",
          "defaultStatus": "unaffected",
          "collectionURL": "https://github.com",
          "packageName": "hexpm/hex",
          "cpes": [
            "cpe:2.3:a:hexpm:hex:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "'Elixir.Hex.HTTP.SSL'"
          ],
          "programFiles": [
            "lib/hex/http/ssl.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.Hex.HTTP.SSL':ssl_opts/1"
            },
            {
              "name": "'Elixir.Hex.HTTP.SSL':partial_chain/2"
            }
          ],
          "repo": "https://github.com/hexpm/hex",
          "packageURL": "pkg:github/hexpm/hex",
          "versions": [
            {
              "version": "c9b26a46928bfcd546773571e09c1d05f4cd9fb7",
              "lessThan": "*",
              "versionType": "git",
              "status": "affected",
              "changes": [
                {
                  "at": "5f5a2136c7cf5991b6e8a30d645ca9f8e74b0785",
                  "status": "unaffected"
                },
                {
                  "at": "6232a6498015e559743bec4f4fbec9138837cec8",
                  "status": "unaffected"
                }
              ]
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "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",
          "baseScore": 5.9,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "HIGH",
          "attackRequirements": "PRESENT",
          "privilegesRequired": "NONE",
          "userInteraction": "ACTIVE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "LOW",
          "vulnAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T17:30:53.768172Z",
          "id": "CVE-2026-103503",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-295"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://cna.erlef.org/cves/CVE-2026-103503.html",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/hexpm/hex/commit/5f5a2136c7cf5991b6e8a30d645ca9f8e74b0785",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/hexpm/hex/commit/6232a6498015e559743bec4f4fbec9138837cec8",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/hexpm/hex/commit/c9b26a46928bfcd546773571e09c1d05f4cd9fb7",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/hexpm/hex/security/advisories/GHSA-rw8q-hg7m-cxgr",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-103503",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    }
  ]
}