Deserialization of Untrusted Data vulnerability in ash-project ash allows an unauthenticated attacker to inject a filter expression through a forged keyset pagination cursor, resulting in SQL injection or code execution depending on the data layer.

Read actions with keyset pagination decode the client-supplied page[:after] or page[:before] cursor in decode_values/2 in lib/ash/page/keyset.ex using non_executable_binary_to_term/2 with [:safe]. That guard blocks new atoms, funs, and ports, but not a struct built from atoms already interned in a running Ash application, so a decoded %Ash.Query.Call{} expression survives and is spliced into the keyset filter as a comparison value in do_filters/4 and evaluated. Because the cursor bypasses the Ash.Expr macro, the runtime never applies the private?/public? gate that would otherwise reject it. On AshPostgres the injected fragment is inlined into the SQL query; on the ETS and Simple data layers it is evaluated in-process as an arbitrary function call.

This issue affects ash: from 1.17.0 before 3.31.3.

AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CWE-89

CWE-502

https://cna.erlef.org/cves/CVE-2026-67579.html

https://github.com/ash-project/ash/commit/91874dd5435bc0ffebd8a254acfa573b39b74520

https://github.com/ash-project/ash/security/advisories/GHSA-3gq3-9xm3-c8v3

https://osv.dev/vulnerability/EEF-CVE-2026-67579

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