CVE-2026-82367 Re-entrant synchronous publish in AshGraphql subscription batcher delivers one subscriber's records to another's topic
Attackers can read other users' subscription data due to a race condition in AshGraphql's batcher when using synchronous publishing modes.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-82367?
CVE-2026-82367 is a low-severity vulnerability in ash-project ash_graphql, published on 30 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Exposure of Data Element to Wrong Session vulnerability in ash-project ash_graphql can deliver one subscription's resolved records to a different subscriber's topic.
AshGraphql.Subscription.Batcher.do_send/5 reads the resolved batch from the process dictionary via Process.get(:batch_resolved) and then unconditionally deletes it. That is sound only inside a task the library owns. On the :backpressure_sync and :noproc fallbacks do_send/5 runs inline in the publishing caller's process, so if a resolver inside an outer do_send/5 triggers another synchronous Ash notification, the inner call finds the outer run's value still under :batch_resolved, adopts it as its own result, and publishes it to the inner topic, a different subscription document with a different actor and tenant. It then deletes the key, so the outer run publishes nothing. The key is not namespaced by run, so records cannot be told apart. The fix saves, clears, and restores :batch_resolved around each run.
This issue affects ash_graphql: from 1.4.0 before 1.11.0.
Weakness: CWE-488
Which versions are affected by CVE-2026-82367?
1 open source package ship an affected version, including ash_graphql.
| Package | Affected | Fixed in |
|---|---|---|
ash_graphql Hex | From 1.4.0 | 1.11.0 |
How do I fix CVE-2026-82367?
Upgrade ash_graphql to 1.11.0 or later.
Is CVE-2026-82367 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82367 exists.
Sources
Also known as EEF-CVE-2026-82367, GHSA-wm4m-cjmc-5v8c.