CVE-2026-69659: Memory exhaustion via unbounded deserialization of keyset pagination cursors in Ash.Page.Keyset

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-09 · updated 2026-10-24
Weakness: CWE-502

Description

Uncontrolled Resource Consumption vulnerability in ash-project ash allows an attacker to exhaust the memory of the node via a crafted keyset pagination cursor. Read actions with keyset pagination deserialize the client-supplied page[:after] or page[:before] cursor in decode_values/2 in lib/ash/page/keyset.ex, which base64-decodes the value and passes it to :erlang.binary_to_term/2 without bounding its size. The Erlang external term format supports zlib-compressed payloads, which the decoder inflates transparently, so a cursor of a few kilobytes can allocate tens of megabytes of heap in a single call. Ash itself only ever encodes cursors uncompressed, so the decoder accepts a term shape its encoder never produces. Concurrent requests aggregate these allocations and can terminate the node. This issue affects ash: from 1.17.0 before 3.31.1.

Affected products

ash-project ash: from 1.17.0 before 3.31.1 — fixed in 3.31.1

How to fix

Upgrade to a fixed version: ash-project ash 3.31.1. Check the vendor advisory for mitigations.

References

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