Executive Summary

CVE-2026-56322 is an information disclosure vulnerability in Capgo versions before 12.128.2. It exists in the unauthenticated /updates endpoint, where the defaultChannel parameter is processed before privacy restrictions are enforced.

This flaw allows attackers to enumerate private channels by probing channel names and distinguishing valid channels from nonexistent ones based on differences in responses.

As a result, attackers can leak sensitive information such as assigned bundle versions and platform-specific configuration details that should be private.

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Impact Analysis

This vulnerability can impact you by exposing sensitive internal information without authentication.

• Attackers can enumerate private channels that are meant to be hidden.
• They can obtain version information and configuration details about your deployment.
• This exposure can weaken the privacy of staged or internal rollout channels.
• It may allow attackers to infer platform enablement status and update version details.

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Detection Guidance

This vulnerability can be detected by probing the unauthenticated /updates endpoint of Capgo with different values for the defaultChannel parameter and observing the responses.

By sending requests that specify various private channel names in the defaultChannel parameter, you can distinguish valid private channels from nonexistent ones based on differences in the responses.

Valid channels will leak sensitive metadata such as assigned bundle versions and platform-specific configuration details, while invalid channels will respond differently.

A possible command to test this could be using curl to send HTTP GET requests to the /updates endpoint with different defaultChannel values, for example:

• curl -v "http://<capgo-server>/updates?defaultChannel=<channel_name>"

By automating such requests with a list of suspected private channel names and analyzing the response differences, you can detect if the vulnerability is present.

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Mitigation Strategies

The primary mitigation step is to upgrade Capgo to version 12.128.2 or later, where this vulnerability has been fixed.

Until the upgrade can be applied, restrict access to the /updates endpoint to authenticated and authorized users only, preventing unauthenticated access.

Additionally, monitor and log access to the /updates endpoint to detect any suspicious probing activity targeting the defaultChannel parameter.

Review and harden privacy enforcement logic to ensure that channel resolution does not occur before privacy restrictions are applied.

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Compliance Impact

CVE-2026-56322 allows unauthenticated attackers to enumerate private channels and leak sensitive version and configuration details due to improper enforcement of privacy restrictions. This exposure of sensitive information to unauthorized actors can weaken privacy protections.

Such information disclosure vulnerabilities can impact compliance with common standards and regulations like GDPR and HIPAA, which require protection of sensitive data and privacy. The leakage of private channel metadata and configuration details may violate data confidentiality requirements and increase risk of unauthorized data exposure.

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