eef-cve-2026-82759

{
  "affected": [
    {
      "database_specific": {
        "source": "https://cna.erlef.org/osv/EEF-CVE-2026-82759.json"
      },
      "package": {
        "ecosystem": "Hex",
        "name": "ash_authentication",
        "purl": "pkg:hex/ash_authentication"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.12.0"
            },
            {
              "fixed": "4.15.0"
            }
          ],
          "type": "SEMVER"
        },
        {
          "events": [
            {
              "introduced": "5.0.0-rc.0"
            },
            {
              "fixed": "5.0.0-rc.14"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": [
        "4.12.0",
        "4.13.0",
        "4.13.1",
        "4.13.2",
        "4.13.3",
        "4.13.4",
        "4.13.5",
        "4.13.6",
        "4.13.7",
        "4.14.0",
        "4.14.1",
        "4.14.2",
        "5.0.0-rc.0",
        "5.0.0-rc.1",
        "5.0.0-rc.10",
        "5.0.0-rc.11",
        "5.0.0-rc.12",
        "5.0.0-rc.13",
        "5.0.0-rc.2",
        "5.0.0-rc.3",
        "5.0.0-rc.4",
        "5.0.0-rc.5",
        "5.0.0-rc.6",
        "5.0.0-rc.7",
        "5.0.0-rc.8",
        "5.0.0-rc.9"
      ]
    },
    {
      "database_specific": {
        "source": "https://cna.erlef.org/osv/EEF-CVE-2026-82759.json"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "255cfc9c0e511b7e0de39f8b3d676ae994fae06c"
            },
            {
              "fixed": "d8a9c4b6bde828fdc8346198d5e4f588b5937541"
            },
            {
              "fixed": "c3a6d5fe0d4fd383ea81b0402db0a96638479478"
            }
          ],
          "repo": "https://github.com/team-alembic/ash_authentication",
          "type": "GIT"
        }
      ],
      "versions": [
        "v4.14.2",
        "v5.0.0-rc.13",
        "v4.14.1",
        "v5.0.0-rc.12",
        "v5.0.0-rc.11",
        "v5.0.0-rc.10",
        "v4.14.0",
        "v4.13.7",
        "5.0.0-rc.9",
        "5.0.0-rc.8",
        "v5.0.0-rc.7",
        "v5.0.0-rc.6",
        "v5.0.0-rc.5",
        "v5.0.0-rc.4",
        "v5.0.0-rc.3",
        "v5.0.0-rc.2",
        "v5.0.0-rc.1",
        "v5.0.0-rc.0",
        "v4.13.6",
        "v4.13.5",
        "v4.13.4",
        "v4.13.3",
        "v4.13.2",
        "v4.13.1",
        "v4.13.0",
        "v4.12.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-82759",
    "GHSA-cgqj-pcpq-xhfm"
  ],
  "credits": [
    {
      "name": "Jonatan Männchen / EEF",
      "type": "ANALYST"
    },
    {
      "name": "James Harton",
      "type": "REMEDIATION_DEVELOPER"
    },
    {
      "name": "Peter Ullrich",
      "type": "REPORTER"
    }
  ],
  "database_specific": {
    "capec_ids": [
      "CAPEC-112"
    ],
    "cpe_ids": [
      "cpe:2.3:a:team-alembic:ash_authentication:*:*:*:*:*:*:*:*"
    ],
    "cwe_ids": [
      "CWE-760"
    ]
  },
  "details": "## Summary\n\nUse of a One-Way Hash with a Predictable Salt vulnerability in team-alembic AshAuthentication allows readers of the audit store to recover the client IP addresses that the audit log add-on's `:hash` privacy mode is meant to pseudonymise.\n\n`AshAuthentication.AddOn.AuditLog.IpPrivacy.hash_ip/1` computes a single unkeyed `:crypto.hash(:sha256, salt <> ip)` and truncates the result to 16 hexadecimal characters. The salt is read from the `:audit_log_ip_salt` or `:secret` application config keys, and falls back to the constant `\"default-salt-change-in-production\"` published in the library source when neither is set, with nothing warning that the default is in use. The IPv4 space is only 2^32 values and SHA-256 is fast, so the whole hash table is precomputable and every stored value maps back to its source address. Truncating to 16 characters does not help, and even a configured salt leaves the hash cheap enough to enumerate once it leaks.\n\nThis issue affects ash_authentication: from 4.12.0 before 4.15.0 and from 5.0.0-rc.0 before 5.0.0-rc.14.\n\n## Configurations\n\nOnly applications that enable the `audit_log` add-on and set its `ip_privacy` mode to `:hash` store the affected value. Other modes (`:none`, `:truncate`, `:exclude`) do not reach `hash_ip/1`.\n\nThe complete break additionally requires the default salt, that is neither `:audit_log_ip_salt` nor `:secret` configured under the `:ash_authentication` application. This is the out-of-the-box state: no warning or error is raised when the hardcoded salt is in use.",
  "id": "EEF-CVE-2026-82759",
  "modified": "2026-09-17T13:26:04.053149254Z",
  "published": "2026-09-17T13:08:21.929Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-cgqj-pcpq-xhfm"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-82759.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/team-alembic/ash_authentication/commit/255cfc9c0e511b7e0de39f8b3d676ae994fae06c"
    },
    {
      "type": "FIX",
      "url": "https://github.com/team-alembic/ash_authentication/commit/d8a9c4b6bde828fdc8346198d5e4f588b5937541"
    },
    {
      "type": "FIX",
      "url": "https://github.com/team-alembic/ash_authentication/commit/c3a6d5fe0d4fd383ea81b0402db0a96638479478"
    },
    {
      "type": "PACKAGE",
      "url": "https://hex.pm/packages/ash_authentication"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Reversible IP address pseudonymisation in AshAuthentication audit log hash mode"
}