# CVE-2026-55518: Avo missing authorization in association attach endpoint

Source: https://junglewise.ai/threats/cve-2026-55518-avo-missing-authorization-in-association-attach-endpoint  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-17. Updated: 2026-07-17  
License: CC BY 4.0 with a link back

CVE-2026-55518 · Severity: critical · CVSS 9.6 · Published 2026-07-17

Avo is a framework used to build administration panels for Ruby on Rails applications. A security flaw was discovered where the system fails to verify user permissions when linking records together via a direct web request, even if the user interface correctly hides the option. This allows a low-privileged user to gain unauthorized access to data or escalate their privileges by manually associating themselves with restricted groups, projects, or administrative roles.

Technologies: [avo (RubyGems)](https://junglewise.ai/threats/technologies/avo). Vendors: [RubyGems](https://junglewise.ai/threats/vendors/rubygems).

## Quick answers

**Is CVE-2026-55518 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55518 being exploited in the wild.

**How severe is CVE-2026-55518?** Critical severity, with a CVSS score of 9.6, published 17 July 2026.

**Which products and versions are affected?** avo (RubyGems) ECOSYSTEM:introduced=0,fixed=3.32.1.

**Is there a fix for CVE-2026-55518?** Yes. avo (RubyGems): upgrade to 3.32.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-55518 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-55518?** Check whether you run avo (RubyGems) 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

- avo (RubyGems): upgrade to 3.32.1 or later

  ```sh
  bundle update avo
  ```


## Technical details

A missing authorization check exists in Avo::AssociationsController#create. While the framework correctly validates the 'attach_<association>?' policy for the UI and the 'new' GET action, it fails to enforce the same policy on the 'create' POST endpoint. An authenticated attacker with low privileges can send a crafted POST request to '/resources/:resource/:id/:related' to mutate associations they are not authorized to modify. This can result in privilege escalation or cross-tenant data access if the associations govern access control (e.g., user-to-role or user-to-tenant relationships). The issue is resolved by ensuring 'authorize_attach_action' is called for both 'new' and 'create' actions.

## Affected products

- avo-hq avo < 3.32.1
- avo-hq avo >= 4.0.0.beta.1, < 4.0.0.beta.51

## Identifiers

- CVE-2026-55518
- GHSA-8fq9-273g-6mrg

## Timeline

- 2026-06-13: patched: Fix merged and released in v3.32.1
- 2026-07-17: disclosed: CVE-2026-55518 published

## References

- [https://github.com/avo-hq/avo/commit/995928e586fd1788dd496bd51c4dbe4a79cb2b9c](https://github.com/avo-hq/avo/commit/995928e586fd1788dd496bd51c4dbe4a79cb2b9c)
- [https://github.com/avo-hq/avo/pull/4568](https://github.com/avo-hq/avo/pull/4568)
- [https://github.com/avo-hq/avo/releases/tag/v3.32.1](https://github.com/avo-hq/avo/releases/tag/v3.32.1)
- [https://github.com/avo-hq/avo/security/advisories/GHSA-8fq9-273g-6mrg](https://github.com/avo-hq/avo/security/advisories/GHSA-8fq9-273g-6mrg)

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