Capgo - Improper Error Handling in Accept Invitation Endpoint via Invalid Magic String
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Information disclosure
- Confidentiality · integrity · availability
- Low · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-209.
Summary
Capgo before 12.128.2 contains improper error handling in the /private/accept_invitation endpoint that returns HTTP 500 instead of safe 4xx errors when magic_invite_string is invalid. Attackers can trigger this vulnerability using only the public key by submitting malformed magic_invite_string values to cause server errors and leak internal processing details.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
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
15 records Highest priority Priority HIGH 8 HIGH, 6 MEDIUM, 1 LOW
Other records, highest priority first
- TI-2026-40665 Capgo - Unauthenticated API Key Validity and Permission Oracle via RPC FunctionsPriority HIGH 77
- TI-2026-40584 Capgo - Unauthenticated RBAC Bindings and Email Disclosure via get_org_user_access_rbac NULL-auth BypassPriority HIGH 77
- TI-2026-40612 Capgo - Privilege Escalation via Cross-Scope RBAC Role AssignmentPriority HIGH 73
Timeline
- 2026-10-02 Threatist record created from CVE-2026-56331
- 2026-10-03 Alias added: GHSA-994r-m5r3-f3p9
References
More Capgo vulnerabilities
- 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
Sources
- CVE-2026-56331 · CVE Program
- CVE-2026-56331 · NVD
- FIRST EPSS
- GHSA-994r-m5r3-f3p9 · GitHub Advisory Database · CC BY 4.0
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