Vulnerability-Lookup

GHSA-HH99-HQG5-6646

Vulnerability from github – Published: 2026-10-05 21:31 – Updated: 2026-10-05 21:31

Details

Filtering 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.

The 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.

This issue affects ash: from 3.5.1 before 3.34.3.

Severity

8.2 (High)


                  
                    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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-94201"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-770"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-05T20:17:28Z",
    "severity": "HIGH"
  },
  "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 \u2014 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": "GHSA-hh99-hqg5-6646",
  "modified": "2026-10-05T21:31:37Z",
  "published": "2026-10-05T21:31:37Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-94201"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ash-project/ash/commit/2970ba3bd5d36d6ad04c731ac87385375d457147"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ash-project/ash/commit/5282f3f513053628cdd1bf2236ea22d975d934d4"
    },
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-94201.html"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-94201"
    }
  ],
  "schema_version": "1.4.0",
  "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/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",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2026-94201 (GCVE-0-2026-94201)

Vulnerability from cvelistv5 – Published: 2026-10-05 19:19 – Updated: 2026-10-06 13:41

Title

Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash

Summary

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. Filtering 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. The 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. This issue affects ash: from 3.5.1 before 3.34.3.

Severity

8.2 (High)


                        
                          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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-06 13:41 UTC

CWE

CWE-770 - Allocation of Resources Without Limits or Throttling

Assigner

EEF mitre root Scorecard

References

4 references

URL	Tags
https://cna.erlef.org/cves/CVE-2026-94201.html	relatedthird-party-advisory
https://osv.dev/vulnerability/EEF-CVE-2026-94201	related
https://github.com/ash-project/ash/commit/2970ba3…	related
https://github.com/ash-project/ash/commit/5282f3f…	patch

Impacted products

2 products

Vendor	Product	Version
ash-project	ash	Affected: 3.5.1 , < 3.34.3 (semver) cpe:2.3:a:ash-project:ash::::::::
ash-project	ash	Affected: 2970ba3bd5d36d6ad04c731ac87385375d457147 , < 5282f3f513053628cdd1bf2236ea22d975d934d4 (git) cpe:2.3:a:ash-project:ash::::::::

Credits

Quinn Wilton Quinn Wilton Zach Daniel / Ash Project Jonatan Männchen / EEF

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-94201",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-06T13:41:07.117450Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-06T13:41:22.142Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "collectionURL": "https://repo.hex.pm",
          "cpes": [
            "cpe:2.3:a:ash-project:ash:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.Ash.Type.Atom\u0027"
          ],
          "packageName": "ash",
          "packageURL": "pkg:hex/ash",
          "product": "ash",
          "programFiles": [
            "lib/ash/type/atom.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.Ash.Type.Atom\u0027:cast_value/2"
            }
          ],
          "repo": "https://github.com/ash-project/ash",
          "vendor": "ash-project",
          "versions": [
            {
              "lessThan": "3.34.3",
              "status": "affected",
              "version": "3.5.1",
              "versionType": "semver"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
            "cpe:2.3:a:ash-project:ash:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unaffected",
          "modules": [
            "\u0027Elixir.Ash.Type.Atom\u0027"
          ],
          "packageName": "ash-project/ash",
          "packageURL": "pkg:github/ash-project/ash",
          "product": "ash",
          "programFiles": [
            "lib/ash/type/atom.ex"
          ],
          "programRoutines": [
            {
              "name": "\u0027Elixir.Ash.Type.Atom\u0027:cast_value/2"
            }
          ],
          "repo": "https://github.com/ash-project/ash",
          "vendor": "ash-project",
          "versions": [
            {
              "lessThan": "5282f3f513053628cdd1bf2236ea22d975d934d4",
              "status": "affected",
              "version": "2970ba3bd5d36d6ad04c731ac87385375d457147",
              "versionType": "git"
            }
          ]
        }
      ],
      "configurations": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eReachable only when an application exposes a public, filterable \u003ccode\u003e:atom\u003c/code\u003e attribute declared with the \u003ccode\u003eunsafe_to_atom?: true\u003c/code\u003e constraint, and an actor can supply filter values for it (for example through AshGraphql, AshJsonApi, or \u003ccode\u003eAsh.Query.filter_input/2\u003c/code\u003e). AshPaperTrail\u0027s version resources ship such an attribute (\u003ccode\u003eversion_action_name\u003c/code\u003e) by default.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "Reachable only when an application exposes a public, filterable `:atom` attribute declared with the `unsafe_to_atom?: true` constraint, and an actor can supply filter values for it (for example through AshGraphql, AshJsonApi, or `Ash.Query.filter_input/2`). AshPaperTrail\u0027s version resources ship such an attribute (`version_action_name`) by default."
            }
          ],
          "value": "Reachable only when an application exposes a public, filterable :atom attribute declared with the unsafe_to_atom?: true constraint, and an actor can supply filter values for it (for example through AshGraphql, AshJsonApi, or Ash.Query.filter_input/2). AshPaperTrail\u0027s version resources ship such an attribute (version_action_name) by default."
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:ash-project:ash:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "3.34.3",
                  "versionStartIncluding": "3.5.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "AND"
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Quinn Wilton"
        },
        {
          "lang": "en",
          "type": "reporter",
          "value": "Quinn Wilton"
        },
        {
          "lang": "en",
          "type": "remediation developer",
          "value": "Zach Daniel / Ash Project"
        },
        {
          "lang": "en",
          "type": "coordinator",
          "value": "Jonatan M\u00e4nnchen / EEF"
        }
      ],
      "dateAssigned": "2026-10-04T15:49:18.000Z",
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eAsh stores \u003ccode\u003e:atom\u003c/code\u003e-typed attributes as strings and compares them as strings. When such an attribute is referenced in a filter, the comparison value is coerced through \u003ccode\u003eAsh.Type.Atom\u003c/code\u003e. Because the type defined no \u003ccode\u003ecoerce/2\u003c/code\u003e callback, coercion fell back to the default (\u003ccode\u003ecast_input/2\u003c/code\u003e), which calls \u003ccode\u003eString.to_atom/1\u003c/code\u003e when the attribute is configured with the \u003ccode\u003eunsafe_to_atom?: true\u003c/code\u003e constraint.\u003c/p\u003e\n\u003cp\u003eFiltering 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 \u003ccode\u003e:atom\u003c/code\u003e attribute declared with \u003ccode\u003eunsafe_to_atom?: true\u003c/code\u003e can exhaust the atom table and crash the node (denial of service). AshPaperTrail is a notable example: its version resources expose a public, filterable \u003ccode\u003eversion_action_name\u003c/code\u003e atom attribute with \u003ccode\u003eunsafe_to_atom?: true\u003c/code\u003e by default.\u003c/p\u003e\n\u003cp\u003eThe fix adds a \u003ccode\u003ecoerce/2\u003c/code\u003e to \u003ccode\u003eAsh.Type.Atom\u003c/code\u003e that never interns atoms \u2014 a comparison value is left as a string, since the type is stored and compared as a string. Setting the attribute from action input (\u003ccode\u003ecast_input/2\u003c/code\u003e, which still honors \u003ccode\u003eunsafe_to_atom?\u003c/code\u003e) is unchanged.\u003c/p\u003e\n\u003cp\u003eThis issue affects ash: from 3.5.1 before 3.34.3.\u003c/p\u003e"
            },
            {
              "base64": false,
              "type": "text/markdown",
              "value": "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 \u2014 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."
            }
          ],
          "value": "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 \u2014 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."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-130",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-130 Excessive Allocation"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 8.2,
            "baseSeverity": "HIGH",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "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",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-770",
              "description": "CWE-770 Allocation of Resources Without Limits or Throttling",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-05T19:19:51.326Z",
        "orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "shortName": "EEF"
      },
      "references": [
        {
          "name": "EEF CNA record for CVE-2026-94201",
          "tags": [
            "related",
            "third-party-advisory"
          ],
          "url": "https://cna.erlef.org/cves/CVE-2026-94201.html"
        },
        {
          "name": "OSV record EEF-CVE-2026-94201",
          "tags": [
            "related"
          ],
          "url": "https://osv.dev/vulnerability/EEF-CVE-2026-94201"
        },
        {
          "name": "Introducing commit 2970ba3 in ash-project/ash",
          "tags": [
            "related"
          ],
          "url": "https://github.com/ash-project/ash/commit/2970ba3bd5d36d6ad04c731ac87385375d457147"
        },
        {
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          "tags": [
            "patch"
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          "url": "https://github.com/ash-project/ash/commit/5282f3f513053628cdd1bf2236ea22d975d934d4"
        }
      ],
      "source": {
        "discovery": "EXTERNAL"
      },
      "title": "Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
    "assignerShortName": "EEF",
    "cveId": "CVE-2026-94201",
    "datePublished": "2026-10-05T19:19:51.326Z",
    "dateReserved": "2026-09-24T09:15:02.216Z",
    "dateUpdated": "2026-10-06T13:41:22.142Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

GHSA-HH99-HQG5-6646

CVE-2026-94201 (GCVE-0-2026-94201)

Tags

Sightings

Nomenclature

Related by attack behaviour