Auth bypass in Cap-Go Capgo
CVE-2026-56280
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.
Vulnerability class: Broken Access Control
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H.
EPSS exploit prediction
EPSS: 0.004 (31.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 31.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Cap-Go Capgo — versions 0, 12.128.2
Weakness classification (CWE)
References
- github.com/Cap-go/capgo/security/advisories/GHSA-95g7-xwwx-j737 (vendor-advisory)
- www.vulncheck.com/advisories/cap-go-privilege-inversion-in-build-log-stream-via… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-56280?
- CVE-2026-56280 is a high-severity vulnerability in Cap-Go Capgo, classified under Missing Authorization. CVSS score: 7.1/10. Published 2026-06-22.
- How severe is CVE-2026-56280?
- High severity. CVSS v3 base score is 7.1 out of 10.