EEF-CVE-2026-81643 CVE-2026-81643 GHSA-j684-hch4-q888
Broken access control in AshGraphql subscription batcher applies authorization suppression to only the first notification
- Severity
- 0.0 / 10
- Unknown · CVSS 4.0
- Exploit chance (EPSS)
- 0.43%
- Chance of exploitation in the next 30 days. Higher than 37.02% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-863 Incorrect Authorization
- Fix
1.11.0- Upgrade ash_graphql to this version or later
Description
Summary
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.
Configurations
The application exposes ash_graphql subscriptions with Ash authorization enabled, and two or more notifications are batched together within the batch interval (the default path).
Affected versions
Hex
| Package | Vulnerable | Fixed in |
|---|---|---|
| ash_graphql | >= 1.4.0, < 1.11.0 |
1.11.0 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
ash_graphql Hex → 1.11.0
- mix
{:ash_graphql, "~> 1.11.0"} # then: mix deps.update ash_graphql
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- Privileges required
- Low
- User interaction
- None
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
Weakness
CWE-863: Incorrect Authorization
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| EEF-CVE-2026-78693 Incomplete redaction re-attaches the original error path in AshGraphql, leaking internal field names | Not rated yet | Also affects ash_graphql |
| EEF-CVE-2026-80223 Cross-tenant subscription disclosure in AshGraphql authorizes notifications in memory without a tenant-scoped read | Not rated yet | Also affects ash_graphql |
| EEF-CVE-2026-81636 Query-complexity limit bypass via first/last pagination arguments in AshGraphql enables denial of service | Not rated yet | Also affects ash_graphql |
| EEF-CVE-2026-81633 Unhandled KeyError in AshGraphql relay node resolution crashes queries via an unknown type segment | Not rated yet | Also affects ash_graphql |
| EEF-CVE-2026-82367 Re-entrant synchronous publish in AshGraphql subscription batcher delivers one subscriber's records to another's topic | Not rated yet | Also affects ash_graphql |
| GHSA-9v7c-q64q-vv33 Nuxt: Dot segments in the request path bypass `server/middleware` path checks and server route rules on page routes | Medium | Same weakness, CWE-863 |
| EEF-CVE-2026-115627 AshPostgres ignores attribute multitenancy on the join resource when loading many_to_many and through relationships, returning records related through other tenants' rows | Not rated yet | Same weakness, CWE-863 |
| EEF-CVE-2026-115635 AshPostgres returns another tenant's record for a skipped upsert when return_skipped_upsert? is set | Not rated yet | Same weakness, CWE-863 |
Credits: Jonatan Männchen / EEF, Peter Ullrich, Zach Daniel / Ash Project
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