{"id":"CVE-2026-94201","title":"Ash stores :atom-typed attributes as strings and compares them as strings","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 f…","severity":"high","cvss":8.2,"cvssVector":"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","cwe":["CWE-770"],"vendor":"ash-project","product":"ash","affected":["ash >= 3.5.1 < 3.34.3","ash-project/ash >= 2970ba3bd5d36d6ad04c731ac87385375d457147 < 5282f3f513053628cdd1bf2236ea22d975d934d4"],"published":"2026-10-05","updated":"2026-10-05","sourceUpdated":"2026-10-05T20:17:28.693","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-94201","references":[{"url":"https://cna.erlef.org/cves/CVE-2026-94201.html","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/ash-project/ash/commit/2970ba3bd5d36d6ad04c731ac87385375d457147","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/ash-project/ash/commit/5282f3f513053628cdd1bf2236ea22d975d934d4","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-94201","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}],"tags":["nvd","cve.org"],"cvssSource":"cna","ingestedAt":"2026-10-05T20:32:56.656Z","slug":"CVE-2026-94201","body":"## Overview\n\nAsh 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":45,"depthScoreParts":{"impact":45.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}