CVE-2026-88862
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.
Scoring
- Severity
- HIGH
- CVSS base score
- 8.8
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CWE
- CWE-863
- Published
- 2026-09-10
- Last modified
- 2026-09-10
Weakness type
Related vulnerabilities
- CVE-2026-88939 — knowns through 0.33.0 Authorization Bypass via project.set Bootstrap Exemption
- CVE-2026-88008 — Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization
- CVE-2026-88007 — Traefik HTTP/3 Backend NTLM Connection Reuse
- CVE-2026-88006 — Open WebUI: Users denied by the OAuth role policy can still sign in via token exchange
- CVE-2026-88005 — Open WebUI: Users denied by the OAuth domain allowlist or role policy can still sign in via token exchange
- CVE-2026-88894 — Snipe-IT before 8.7.2 Authorization Bypass via Predefined Kit Checkout
- CVE-2026-88884 — Renovate before 44.3.1 Authentication Bypass via Digest Updates
- CVE-2026-88860 — Capgo Authorization Bypass via Stale Channel Permission Overrides