CVE-2026-81643: Broken access control in AshGraphql subscription batcher applies authorization suppression to only the first notification

Severity: low (CVSS 2.3 v4.0)
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: 2026-08-30 · updated 2026-09-01
Weakness: CWE-863

Description

Incorrect Authorization vulnerability in ash-project ash_graphql delivers GraphQL subscription payloads for records a subscriber is not authorized to see. In AshGraphql.Subscription.Batcher, do_send/5 resolves the first notification of a batch and filters it with should_send?/1, which drops results whose errors are coded forbidden or not_found or carry no code, precisely so that unauthorized results are not disclosed. The remaining notifications in the batch are read from the process dictionary, re-run through the pipeline, and appended to the outgoing results without that filter. They reach pubsub.publish_subscription/2, and the not is_nil(record) guard drops only nil records, not error-carrying results. Any two qualifying notifications arriving within the default one-second batch interval suffice, and batching is the default path. The fix applies should_send?/1 to the whole batch. This issue affects ash_graphql: from 1.4.0 before 1.11.0.

Affected products

ash-project ash_graphql: from 1.4.0 before 1.11.0 — fixed in 1.11.0

How to fix

Upgrade to a fixed version: ash-project ash_graphql 1.11.0. Check the vendor advisory for mitigations.

References

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