{"id":"CVE-2026-88862","title":"Capgo (capgo.app) backend through 12.242.4 does not validate parent-child delegation when processing the x-limited-key-id header","summary":"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 num…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-863"],"vendor":"Cap-go","product":"capgo.app","affected":["capgo.app"],"published":"2026-09-10","updated":"2026-09-10","sourceUpdated":"2026-09-10T15:17:56.617","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-88862","references":[{"url":"https://github.com/Cap-go/capgo.app/security/advisories/GHSA-5hjr-xhx8-x5j7","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/capgo-api-key-manager-authentication-bypass-via-x-limited-key-id","label":"disclosure@vulncheck.com"},{"url":"https://github.com/Cap-go/capgo.app/security/advisories/GHSA-5hjr-xhx8-x5j7","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"tags":["nvd","cve.org","exploit-available"],"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"total","timestamp":"2026-09-10T14:26:27.714255Z"},"ingestedAt":"2026-09-10T13:50:37.334Z","epss":0.00311,"epssPercentile":0.2416,"slug":"CVE-2026-88862","body":"## Overview\n\nCapgo (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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":60,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":12,"ransomware":0},"changes":[{"seq":47819,"id":"CVE-2026-88862","ts":1789051952856,"field":"exploit_available","old":"false","new":"true"}]}