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TI-2026-40671 Aliases CVE-2026-56306

Capgo - Subkey Enforcement Bypass via x-limited-key-id Header Parsing

Priority MEDIUM 57CWE-20Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

Capgo before 12.128.2 contains a weak parsing vulnerability in the x-limited-key-id header that allows attackers to bypass subkey enforcement by submitting malformed values, zero, or duplicate headers that result in NaN or falsy values. Remote attackers can manipulate the x-limited-key-id header to disable limited key scoping and execute requests using the main API key context instead of restricted subkey permissions.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00302 23rd percentileScored 2026-11-07
Fix Fixed Capgo (Capgo): 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 (Capgo) 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 ·

    Capgo 12.128.2

    6 records Highest priority Priority HIGH 3 HIGH, 2 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-40689 Capgo - Rate Limit Bypass via User-Controlled device_id ParameterPriority HIGH 77
    • TI-2026-40688 Capgo - Unauthenticated Channel Enumeration and App Oracle via GET /channel_selfPriority HIGH 77
    • TI-2026-40676 Capgo - Unauthenticated Cross-Tenant Disclosure via get_current_plan_max_org RPCPriority HIGH 70
    Show all 6 records →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-56306

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