Quick answers
- Is CVE-2026-77856 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-77856 being exploited in the wild.
- How severe is CVE-2026-77856?
- Informational severity, published 1 September 2026.
- Which products and versions are affected?
- Ash-Project Ash Typescript 0.11.0 to 0.17.x.
- Is there a fix for CVE-2026-77856?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-77856 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-77856?
- Check whether you run Ash-Project Ash Typescript at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is a resource exhaustion flaw in the resolve_typed_struct_field/2 function (lib/ash_typescript/rpc/field_processing/field_selector.ex). When processing client-supplied typed struct field names, the code performs a reverse map lookup and falls back to String.to_atom/1 if no match is found, before validating whether the field actually exists. Since atoms in Erlang are never garbage collected, an attacker can trigger creation of unlimited unique atoms by sending requests with many distinct invalid field names. Once the VM's atom table limit is reached, the entire BEAM node aborts. The attack requires network access to the affected endpoint but no authentication. Patches are available in ash_typescript version 0.18.0 and later.
Affected products
- ash-project ash_typescript 0.11.0 to 0.17.x
Timeline
- 2026-09-01: disclosed
- 2026-09-01: advisory: CVE-2026-77856