# CVE-2026-56280: Cap-go privilege inversion in build log stream via SSE disconnect

Source: https://junglewise.ai/threats/cve-2026-56280-cap-go-privilege-inversion-in-build-log-stream-via-sse-disconnect  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-22. Updated: 2026-06-22  
License: CC BY 4.0 with a link back

CVE-2026-56280 · Severity: high · CVSS 7.1 · Published 2026-06-22

Cap-go is a service used for managing and deploying mobile app updates. A security flaw allows users with restricted, read-only access to prematurely cancel active app builds by simply disconnecting from a log stream. This can be used by malicious insiders or compromised accounts to disrupt development workflows and prevent teams from successfully building or deploying their software.

## Quick answers

**Is CVE-2026-56280 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-56280 being exploited in the wild.

**How severe is CVE-2026-56280?** High severity, with a CVSS score of 7.1, published 22 June 2026.

**Which products and versions are affected?** Cap-go capgo < 12.128.2.

**Is there a fix for CVE-2026-56280?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-56280 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-56280?** Check whether anything you run is named in the advisory. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A privilege inversion vulnerability exists in the 'GET /build/logs/:jobId' endpoint of Cap-go. While the endpoint itself is restricted to 'app.read_logs' permissions, it registers an abort listener on the Server-Sent Events (SSE) stream that unconditionally triggers 'cancelBuildOnDisconnect()'. This function executes the cancellation using a privileged server-side 'BUILDER_API_KEY', bypassing the 'app.build_native' write permission check enforced on the standard cancellation endpoint. An attacker with a valid read-only API key can disrupt CI/CD workflows by initiating a log stream and abruptly dropping the TCP connection, causing the server to terminate the associated build job. This issue is resolved in version 12.128.2.

## Affected products

- Cap-go capgo < 12.128.2

## Timeline

- 2026-05-07: advisory: GitHub Security Advisory GHSA-95g7-xwwx-j737 published
- 2026-06-22: disclosed: CVE-2026-56280 published to NVD

## References

- [https://github.com/Cap-go/capgo/security/advisories/GHSA-95g7-xwwx-j737](https://github.com/Cap-go/capgo/security/advisories/GHSA-95g7-xwwx-j737)
- [https://www.vulncheck.com/advisories/cap-go-privilege-inversion-in-build-log-stream-via-sse-disconnect](https://www.vulncheck.com/advisories/cap-go-privilege-inversion-in-build-log-stream-via-sse-disconnect)