Capgo (capgo.app) backend through 12.242.4 does not validate parent-child delegation when processing the x-limited-key-id header. checkKeyByIdPg() in supabase/functions/_backend/utils/hono_middleware.ts resolves the attacker-supplied numeric API key ID using only the key ID, its expiration state, and the authenticating key's user_id, while hasLimitedRbacSubkeyScope() accepts any key with a non-organization (e.g., app-scoped) RBAC binding and validateSubkeyUser() only compares owning user IDs. Because Capgo treats API keys as independent RBAC principals with separate role bindings, an authenticated apikey_manager API key with no application access can supply the numeric ID of a more privileged same-owner key and have the middleware replace the authenticated principal and effective API-key secret with that key (setSubkeyAuthContext), exercising an app_admin sibling's permissions without knowing or submitting its secret. The issue was reproduced on release 12.242.4 (commit b3d02cdbc23ac59990785acacd1f113c07458568) after the fix for GHSA-8h52-44r7-w343; at the time of the advisory no patched version was available.
Metrics
Affected Vendors & Products
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History
Thu, 10 Sep 2026 15:30:00 +0000
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Thu, 10 Sep 2026 13:30:00 +0000
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| Description | Capgo (capgo.app) backend through 12.242.4 does not validate parent-child delegation when processing the x-limited-key-id header. checkKeyByIdPg() in supabase/functions/_backend/utils/hono_middleware.ts resolves the attacker-supplied numeric API key ID using only the key ID, its expiration state, and the authenticating key's user_id, while hasLimitedRbacSubkeyScope() accepts any key with a non-organization (e.g., app-scoped) RBAC binding and validateSubkeyUser() only compares owning user IDs. Because Capgo treats API keys as independent RBAC principals with separate role bindings, an authenticated apikey_manager API key with no application access can supply the numeric ID of a more privileged same-owner key and have the middleware replace the authenticated principal and effective API-key secret with that key (setSubkeyAuthContext), exercising an app_admin sibling's permissions without knowing or submitting its secret. The issue was reproduced on release 12.242.4 (commit b3d02cdbc23ac59990785acacd1f113c07458568) after the fix for GHSA-8h52-44r7-w343; at the time of the advisory no patched version was available. | |
| Title | Capgo API Key Manager Authentication Bypass via x-limited-key-id | |
| Weaknesses | CWE-863 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: VulnCheck
Published: 2026-09-10T13:05:19.116Z
Updated: 2026-09-10T14:27:28.766Z
Reserved: 2026-09-10T11:23:56.027Z
Link: CVE-2026-88862
Updated: 2026-09-10T14:26:45.451Z
Status : Deferred
Published: 2026-09-10T14:17:11.820
Modified: 2026-09-10T15:17:56.617
Link: CVE-2026-88862
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