{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "3.5.1"
              },
              {
                "fixed": "3.34.3"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "2970ba3bd5d36d6ad04c731ac87385375d457147"
            },
            {
              "fixed": "5282f3f513053628cdd1bf2236ea22d975d934d4"
            },
            {
              "introduced": "c5d533ea0331333456bd768a0b23660224efcc9e"
            },
            {
              "fixed": "8df3aeabbf8fbf801d4bcb7bce2e81bea550fd10"
            }
          ],
          "repo": "https://github.com/ash-project/ash",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-770"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/94xxx/CVE-2026-94201.json"
  },
  "details": "Ash stores :atom-typed attributes as strings and compares them as strings. When such an attribute is referenced in a filter, the comparison value is coerced through Ash.Type.Atom. Because the type defined no coerce/2 callback, coercion fell back to the default (cast_input/2), which calls String.to_atom/1 when the attribute is configured with the unsafe_to_atom?: true constraint.\n\nFiltering such an attribute with attacker-controlled strings therefore interned a new, permanent atom for every distinct value. Atoms are never garbage collected and the BEAM caps the atom table, so an actor who can supply filter values for a public, filterable :atom attribute declared with unsafe_to_atom?: true can exhaust the atom table and crash the node (denial of service). AshPaperTrail is a notable example: its version resources expose a public, filterable version_action_name atom attribute with unsafe_to_atom?: true by default.\n\nThe fix adds a coerce/2 to Ash.Type.Atom that never interns atoms — a comparison value is left as a string, since the type is stored and compared as a string. Setting the attribute from action input (cast_input/2, which still honors unsafe_to_atom?) is unchanged.\n\nThis issue affects ash: from 3.5.1 before 3.34.3.",
  "id": "CVE-2026-94201",
  "modified": "2026-10-10T02:31:02.418774233Z",
  "published": "2026-10-05T19:19:51.326Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-94201"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://cna.erlef.org/cves/CVE-2026-94201.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/94xxx/CVE-2026-94201.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-94201"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ash-project/ash/commit/2970ba3bd5d36d6ad04c731ac87385375d457147"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ash-project/ash/commit/5282f3f513053628cdd1bf2236ea22d975d934d4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ash-project/ash"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash"
}