# CVE-2021-29452: Curveball a12n-server privilege escalation in user editing

Source: https://junglewise.ai/threats/cve-2021-29452-curveball-a12n-server-privilege-escalation-in-user-editing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-04-19. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2021-29452 · Severity: low · CVSS 3.1 · Published 2021-04-19

Curveball a12n-server is an authentication and user management service. A vulnerability in user editing allows any logged-in user to modify other users' accounts without proper authorization checks, potentially leading to account takeover and unauthorized privilege escalation.

Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2021-29452 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2021-29452 being exploited in the wild.

**How severe is CVE-2021-29452?** Low severity, with a CVSS score of 3.1, published 19 April 2021.

**Which products and versions are affected?** Curveball A12n-Server 0.18.0 to 0.18.1; @curveball/a12n-server (npm) SEMVER:introduced=0.18.0,fixed=0.18.2.

**Is there a fix for CVE-2021-29452?** Yes. @curveball/a12n-server (npm): upgrade to 0.18.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2021-29452 attacked?** It is attacked over the network.

**Am I affected by CVE-2021-29452?** Check whether you run Curveball A12n-Server or @curveball/a12n-server (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- @curveball/a12n-server (npm): upgrade to 0.18.2 or later

  ```sh
  npm install @curveball/a12n-server@0.18.2
  ```


## Technical details

A newly added HAL-Form for user editing failed to properly enforce admin-only access controls due to incorrect privilege validation. The vulnerability affects versions 0.18.0 through 0.18.1, allowing any authenticated user to modify any other user account, including changing credentials and potentially elevating privileges. The attack requires network access and valid credentials (CWE-269: Improper Access Control / CWE-863: Incorrect Authorization). The vulnerability is patched in version 0.18.2.

## Affected products

- Curveball a12n-server 0.18.0 to 0.18.1

## Identifiers

- CVE-2021-29452
- GHSA-8hw9-22v6-9jr9

## Timeline

- 2021-04-16: disclosed: GitHub advisory published
- 2021-04-19: patched: Fix released in version 0.18.2

## References

- [https://github.com/curveball/a12n-server/security/advisories/GHSA-8hw9-22v6-9jr9](https://github.com/curveball/a12n-server/security/advisories/GHSA-8hw9-22v6-9jr9)

## Related threats

- [a12nserver SQL injection via Knex dependency](https://junglewise.ai/threats/a12nserver-sql-injection-via-knex-dependency-846aaafa)