CVE-2026-56280 Cap-go - Privilege Inversion in Build Log Stream via SSE Disconnect
Read-only API key holders can cancel running native builds by disconnecting from the log stream, bypassing permission checks and disrupting CI/CD workflows.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-56280?
CVE-2026-56280 is a high-severity missing authorization vulnerability in Cap-go capgo, published on 22 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Cap-go before 12.128.2 contains a privilege inversion vulnerability in GET /build/logs/:jobId that allows read-only API key holders to cancel running native builds. The endpoint registers an abort listener on the SSE stream that unconditionally invokes cancelBuildOnDisconnect() using the privileged server-side BUILDER_API_KEY when clients disconnect, bypassing the app.build_native permission check required by the explicit POST /build/cancel/:jobId endpoint. Attackers with read-only API keys can repeatedly disrupt native build operations and CI/CD workflows by opening the log stream and dropping the connection.
Weakness: CWE-862
Which versions are affected by CVE-2026-56280?
How do I fix CVE-2026-56280?
No fix has been published for CVE-2026-56280 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-56280 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-56280 exists.
Sources
Also known as GHSA-95g7-xwwx-j737.