CVE-2026-77856

Unbounded atom creation from typed struct field names in AshTypescript field selector

HIGH
8.2
CVSS Score
Published: September 1, 2026 at 02:08 AM UTC
Updated: September 1, 2026 at 09:31 PM UTC
1 product affected across 1 vendorAshTypescript

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Severity
HIGH8.2
Exploit prediction
EPSS 0.5%
SSVC
PoC

Description

Allocation of Resources Without Limits or Throttling vulnerability in ash-project ash_typescript allows an unauthenticated attacker to exhaust the BEAM atom table and abort the node via client-supplied typed struct field names. resolve_typed_struct_field/2 in lib/ash_typescript/rpc/field_processing/field_selector.ex looks a client-supplied field name up in the typed struct's reverse map and, when it finds no match, falls back to String.to_atom/1. Because this runs before any field-existence check, an unresolvable name mints a permanent atom rather than being rejected as unknown. Atoms are never garbage collected, so a request carrying many distinct names on a typed struct field grows the atom table until the VM aborts at its limit. This issue affects ash_typescript: from 0.11.0 before 0.18.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.11.0 ≤ v < 0.18.00.11.07c3d30896f2f9a54edea17e3787549776b1b288d
Vendor states this is fixed in 0ab5c83a7df28d51a6de1fb9b859a142b2b12919 (fixed)
Affected range stops below 0.18.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.2HIGHEEF
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-770

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