Vulnerability in Cap-go (CVE-2026-56280)
Summary
Vulnerability in Cap-go (CVE-2026-56280). Risk of unauthorized operations or information disclosure. Exploitable via GET /build/logs/.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-56280 has been found in Cap-go.
Attackers can target a specific entry point like GET /build/logs/ over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Cap-go CVE-2026-56280" on the vendor's site.
CVE-2026-56280 (Cap-go) — CWE-862 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: GET /build/logs/ / POST /build/cancel/
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-862) exists in Cap-go. Attackers reach the vulnerable code path via GET /build/logs/.
Check the vendor advisory for the affected versions of Cap-go. Attack surface: GET /build/logs/ / POST /build/cancel/.
Severity: High (CVSS 7.1/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /build/logs/ requests with malformed payloads or SQL meta-characters. Run grep -r 'Cap-go' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Cap-go' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Cap-goを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /build/logs/' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /build/logs/への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Post-deployment verification verify
Replay attack against GET /build/logs/ on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
References
- advisory github.com
- advisory vulncheck.com
- advisory github.com
- advisory nvd.nist.gov