---
id: CVE-2026-56296
title: >-
  Cap-go before 12.128.2 contains an information disclosure vulnerability in the
  public.transfer_app RPC function that returns distinct error messages for
  existing versus non-existing app IDs
summary: >-
  Cap-go before 12.128.2 contains an information disclosure vulnerability in the
  public.transfer_app RPC function that returns distinct error messages for
  existing versus non-existing app IDs. Unauthenticated attackers can enumerate
  valid …
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'
cwe:
  - CWE-203
published: '2026-07-11'
updated: '2026-07-11'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-56296'
references:
  - url: 'https://github.com/Cap-go/capgo/security/advisories/GHSA-fmm3-3qcg-85j6'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/cap-go-app-existence-oracle-via-unauthenticated-transfer-app-rpc
    label: disclosure@vulncheck.com
tags:
  - nvd
ingestedAt: '2026-07-11T23:16:21.015Z'
epss: 0.00358
epssPercentile: 0.29638
---

## Overview

Cap-go before 12.128.2 contains an information disclosure vulnerability in the public.transfer_app RPC function that returns distinct error messages for existing versus non-existing app IDs. Unauthenticated attackers can enumerate valid app IDs by observing error message differences when calling transfer_app with only the publishable API key.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.