CVE-2026-56255 Capgo CVE debrief

Who should care

Organizations using Capgo versions prior to 12.128.2 should be aware of this vulnerability and take steps to mitigate it. Specifically, administrators of Capgo instances should prioritize updating to version 12.128.2 or later to prevent potential denial of service attacks. Additionally, users with org write permissions should be cautious when creating demo applications to avoid unintentionally triggering the vulnerability.

Technical summary

The vulnerability in Capgo arises from the lack of rate limiting and quota enforcement in the POST /app/demo endpoint. Authenticated users with org write permissions can exploit this by creating unlimited demo applications, leading to a significant increase in database write operations. This can result in degraded performance, increased costs due to excessive database usage, and potential service instability. The vulnerability has a CVSS score of 5.3, indicating a medium severity level. The issue is addressed in Capgo version 12.128.2.

Defensive priority

Defenders should prioritize updating Capgo to version 12.128.2 or later to mitigate this vulnerability. In the interim, organizations can consider implementing additional monitoring and rate limiting measures to detect and prevent potential abuse of the /app/demo endpoint.

Recommended defensive actions

• Update Capgo to version 12.128.2 or later.
• Implement additional monitoring and rate limiting measures for the /app/demo endpoint.
• Restrict org write permissions to minimize the number of users who can exploit the vulnerability.
• Regularly review and audit demo application creation to detect potential abuse.
• Consider implementing compensating controls, such as IP blocking or user account limiting, to prevent excessive demo application creation.

Evidence notes

The CVE-2026-56255 vulnerability was published on June 22, 2026, and last modified on June 23, 2026. The vulnerability affects Capgo versions prior to 12.128.2. The CVSS score for this vulnerability is 5.3, indicating a medium severity level. The vulnerability allows authenticated users with org write permissions to create unlimited demo applications, leading to approximately 138 database write operations per request.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.