CVE-2026-88862 Capgo API Key Manager Authentication Bypass via x-limited-key-id
Authenticated attackers can bypass API key restrictions by supplying a privileged key ID in headers, gaining unauthorized application admin permissions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-88862?
CVE-2026-88862 is a high-severity authentication bypass vulnerability in Cap-go capgo.app, published on 10 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-863
Which versions are affected by CVE-2026-88862?
How do I fix CVE-2026-88862?
No fix has been published for CVE-2026-88862 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-88862 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-88862 exists.
Sources
Also known as GHSA-5hjr-xhx8-x5j7, GHSA-92q7-3qv3-754g.