GHSA/SYNC: 1 new avo advisory (#1126)

Author: jasnow

gems/avo/CVE-2026-55518.yml

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+---
+gem: avo
+cve: 2026-55518
+ghsa: 8fq9-273g-6mrg
+url: https://www.cve.org/CVERecord?id=CVE-2026-55518
+title: Avo - Missing Authorization in Avo Association Attach Endpoint
+  Allows Unauthorized Relationship Manipulation and Privilege Escalation
+date: 2026-06-17
+description: |
+  ## Summary
+
+  A critical missing authorization flaw exists in Avo's association attach
+  workflow. The UI and `GET /resources/:resource/:id/:related/new` path
+  can check `attach_<association>?`, but the actual write endpoint,
+  `POST /resources/:resource/:id/:related`, does not run the same
+  authorization check before mutating the association.
+
+  As a result, an authenticated low-privileged Avo user can bypass
+  hidden/disabled attach controls and directly attach related records
+  to a parent record by sending a crafted POST request. In applications
+  where associations represent teams, tenants, roles, projects, users,
+  memberships, ownership, or other authorization-bearing relationships,
+  this can lead to privilege escalation and cross-tenant data exposure.
+
+  ## Impact
+
+  This vulnerability allows unauthorized relationship manipulation
+  through Avo.
+
+  Depending on the affected association, the impact can include:
+
+  - Privilege escalation by attaching a user to an admin group,
+    privileged project, tenant, organization, role, or membership record.
+  - Cross-tenant data exposure when tenant/user/project membership
+    determines record visibility.
+  - Integrity loss by changing ownership, assignment, access-control
+    relationships, or business workflow state.
+  - Policy bypass even when Avo UI controls correctly hide the attach
+    button or deny the attach form.
+cvss_v3: 9.6
+patched_versions:
+  - "~> 3.32.1"
+  - ">= 4.0.0.beta.51"
+related:
+  url:
+    - https://www.cve.org/CVERecord?id=CVE-2026-55518
+    - https://advisories.gitlab.com/gem/avo/CVE-2026-55518
+    - https://github.com/avo-hq/avo/security/advisories/GHSA-8fq9-273g-6mrg
+    - https://github.com/advisories/GHSA-8fq9-273g-6mrg
+notes: |
+  - cvss_v3 from GHSA, no value for cvss_v2 or cvss_v4
+  - CVE is reserved, but not published