SEPTEMBER 15, 2026
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Case File

CVE-2026-88862

HIGH · CVSS 8.8 EPSS 0.31% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-10 · Last synced 2026-09-15

CyberRota Analysis

AI-Generated

The vulnerability affects the Capgo backend, where improper validation of the x-limited-key-id header allows an authenticated user with an apikey_manager role to impersonate a more privileged API key, thereby gaining unauthorized access to elevated permissions. This flaw can lead to significant security breaches, as it enables attackers to exploit the permissions of app_admin roles without needing the actual secret. Organizations using Capgo, particularly those managing sensitive data or critical applications, should prioritize addressing this vulnerability to mitigate potential risks.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

GitHub PoC Links

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-88862
Severity
HIGH
CVSS
8.8
EPSS
0.31%

Original NVD 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.