Vulnerability · Published Sep 1, 2026 · Assigned by EEF
CVE-2026-77856Unbounded atom creation from typed struct field names in AshTypescript field selector
High 8.2
In plain English
A high-severity resource allocation without limits in ash_typescript from ash-project. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities).
Official 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 products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| ash-project | ash_typescript | 0.11.0 – before 0.18.0 |
| ash-project | ash_typescript | 7c3d30896f2f9a54edea17e3787549776b1b288d – before 0ab5c83a7df28d51a6de1fb9b859a142b2b12919 |
Weakness: CWE-770 · Vector: 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
References
- https://github.com/ash-project/ash_typescript/security/advisories/GHSA-rj47-h936-4cxw related, vendor-advisory
- https://cna.erlef.org/cves/CVE-2026-77856.html related
- https://osv.dev/vulnerability/EEF-CVE-2026-77856 related
- https://github.com/ash-project/ash_typescript/commit/0ab5c83a7df28d51a6de1fb9b859a142b2b12919 patch