CVE-2026-30863
Parse Server: JWT audience validation bypass in Google, Apple, and Facebook authentication adapters
Description
### Impact The Google, Apple, and Facebook authentication adapters use JWT verification to validate identity tokens. When the adapter's audience configuration option is not set (`clientId` for Google/Apple, `appIds` for Facebook), JWT verification silently skips audience claim validation. This allows an attacker to use a validly signed JWT issued for a different application to authenticate as any user on the target Parse Server. - For Google and Apple, the vulnerability is exploitable when the server does not configure `clientId`. The adapters accepted this as valid and simply skipped audience validation. - For Facebook Limited Login, the vulnerability exists regardless of configuration. The adapter validated `appIds` only for Standard Login (Graph API), but the Limited Login JWT path never passed `appIds` as the audience to JWT verification. ### Patches The fix enforces `clientId` (Google/Apple) and `appIds` (Facebook) as mandatory and passes them to JWT verification for audience validation. While this is technically a breaking change for servers that omit these options, it is not a breaking change as per documentation — all three options are documented as required configuration. ### Workarounds - Google / Apple: Ensure `clientId` is set in the adapter configuration. When set, JWT verification correctly validates the audience claim even on unpatched versions. - Facebook Limited Login: There is no workaround. The unpatched adapter does not pass `appIds` to JWT audience validation, so the only mitigation is to upgrade. ### References - GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-x6fw-778m-wr9v - Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.0-alpha.11 - Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.10
How to fix CVE-2026-30863
To remediate CVE-2026-30863, upgrade the affected package to a fixed version below.
- —upgrade to 9.5.0 or later
- —upgrade to 9.5.0-alpha.11 or later
Is CVE-2026-30863 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.