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TI-2026-40645 Aliases CVE-2026-56280

Cap-go - Privilege Inversion in Build Log Stream via SSE Disconnect

Priority MEDIUM 64CWE-862Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Security bypass
Confidentiality · integrity · availability
None · Low · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-862.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00316 24th percentileScored 2026-11-07
Fix Fixed capgo (Cap-go): 12.128.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Capgocapgobefore 12.128.212.128.2Patch availableCNA
  • capgo VendorCapgo Affected before 12.128.2 Fixed in 12.128.2 Patch available CNA

Remediation

  • Fix · CNA capgo (Cap-go) Fixed in 12.128.2

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Cap-go capgo 12.128.2

    2 records Highest priority Priority MEDIUM 2 MEDIUM

    Other records, highest priority first

    • TI-2026-40586 Cap-go - SQL Injection in Cloudflare Analytics Engine Queries via cloudflare.tsPriority MEDIUM 64
    Show all 2 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-56280

References

Advisory 1

  • TI-2026-40602 Capgo - Unauthenticated API Key Generation via Client-Side Parameter Manipulation CVSS 4.0CRITICAL 9.3
  • TI-2026-40473 Cap-go - Account Lockout via 2FA Misconfiguration on Unverified Email CVSS 4.0CRITICAL 9.3
  • TI-2026-40465 Cap-go - OTP Bypass via Response Manipulation in Email Verification CVSS 4.0CRITICAL 9.3
  • TI-2026-64782 capgo.app through 12.129.0 Cache Restoration of Deleted Bundles CVSS 4.0HIGH 8.7
  • TI-2026-40704 Capgo - Unauthenticated Organization Existence Enumeration via rescind_invitation RPC CVSS 4.0HIGH 8.7
  • TI-2026-40689 Capgo - Rate Limit Bypass via User-Controlled device_id Parameter CVSS 4.0HIGH 8.8
See all 124 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences