vulnerability / NVI-00018387 / Revision 1
Appsmith Super User Creation Race Condition Allows Multiple Instance Administrators
GitHub lists this reviewed advisory for com.appsmith:server. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
8.1 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
com.appsmith:server
source listed< 1.99.0
## Summary The `/api/v1/users/super` endpoint enforces a restriction that only one super user (Instance Administrator) can be created during initial setup. However, due to a Time-of-Check-Time-of-Use (TOCTOU) race condition in the `signupAndLoginSuper()` method, concurrent requests can bypass this restriction, allowing multiple unauthorized users to obtain Instance Administrator privileges. ## Severity - **CWE**: CWE-367 (Time-of-Check Time-of-Use Race Condition) - **CVSS 3.1**: AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H — **8.1 (HIGH)** ## Affected Version - Appsmith Community Edition v1.97.0-SNAPSHOT (release branch) - Docker image: `appsmith/appsmith-ce:release` (pulled 2026-02-25) - Commit: `55ac824f8d42f934cc7a69f8abc52880a6ad39ef` ## Root Cause The `signupAndLoginSuper()` method in `UserSignupCEImpl.java` (lines 270–295) performs a non-atomic check-then-act sequence: ```java // Step 1: CHECK — query MongoDB for existing users userService.isUsersEmpty() .flatMap(isEmpty -> { if (!Boolean.TRUE.equals(isEmpty)) { return Mono.error(new AppsmithException(AppsmithError.UNAUTHORIZED_ACCESS)); } // Step 2: ACT — create user and grant admin (no
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-9wcp-79g5-5c3c ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.