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HIGH

CVE-2026-94201

CVE-2026-94201 — Filtering an :atom attribute with unsafe_to_atom? can exhaust the BEAM atom table in Ash

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…

Published Updated Sources: cvelistV5, EEF

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Unreported

no source claims exploitation

EPSS

0%

chance of exploitation in 30 days

Affects

ash project

ash

CVSS base

8.2

HIGH

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

None

none · proof-of-concept · active

Automatable

No

can an attacker script all four kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Affected scope

The catalog records vendors and products as separate lists, not pairs, so which product belongs to which vendor is not something this page can say.

Vendors (1)

ash project

Products (1)

ash

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactSource
8.2CVSS 4.0HIGH——cvelistV5

Weakness & attack patterns

  • CWE-770

Attack patterns reported against this CVE. The ATT&CK techniques below are inferred from its weakness class.

  • T1498.001Network Denial of Service: Direct Network Flood
  • T1499Endpoint Denial of Service
  • T1499.003Endpoint Denial of Service: Application Exhaustion Flood

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

  • Search application, proxy, and WAF logs for requests touching /2, /2), /1.

References

4 on the record

Elsewhere on this site

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.