Vulnerability in avo (CVE-2026-55518)
Summary
Vulnerability in avo (CVE-2026-55518). Confidential information can be exposed externally. Exploitable via GET /resources/. Mitigation: upgrade to 4.0.0.beta.51 or later.
Original description
The description as published by the source.
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_?, 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.
Details
The association attach route writes relationships through Avo::AssociationsController#create:
# config/routes.rb
post "/:resource_name/:id/:related_name", to: "associations#create", as: "associations_create"
The controller registers an attach authorization callback only for new, not for create:
# app/controllers/avo/associations_controller.rb
before_action :set_attachment_record, only: [:create, :destroy]
before_action :authorize_index_action, only: :index
before_action :authorize_attach_action, only: :new
before_action :authorize_detach_action, only: :destroy
The new action is only the form-rendering step. The actual mutation happens in create:
def create
if create_association
create_su…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-55518 has been found in avo.
Attackers can target a specific entry point like GET /resources/ over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 9.6/10.
What to do: upgrade avo to 4.0.0.beta.51 or later.
If unsure, ask your IT team or search "avo CVE-2026-55518" on the vendor's site.
CVE-2026-55518 (avo) — CWE-639 / CVSS v3 9.6
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /resources/ / POST /resources/ / GET /admin/resources/projects/1/users/new / POST /admin/resources/projects/1/users
Patched: 4.0.0.beta.51 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-639) exists in avo. Attackers reach the vulnerable code path via GET /resources/.
Check the vendor advisory for the affected versions of avo. Attack surface: GET /resources/ / POST /resources/ / GET /admin/resources/projects/1/users/new / POST /admin/resources/projects/1/users.
Severity: Critical (CVSS 9.6/10). Confidential information can be exposed externally.
Update to 4.0.0.beta.51.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /resources/ requests with malformed payloads or SQL meta-characters. Run grep -r 'avo' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'avo' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
avoを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /resources/' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /resources/への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade avo to 4.0.0.beta.51ステージング環境で 4.0.0.beta.51 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /resources/ on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web cve.org