CVE-2026-33624

Description

### Impact An attacker who obtains a user's password and a single MFA recovery code can reuse that recovery code an unlimited number of times by sending concurrent login requests. This defeats the single-use design of recovery codes. The attack requires the user's password, a valid recovery code, and the ability to send concurrent requests within milliseconds. ### Patches The login handler now uses optimistic locking when updating auth data that contains consumed single-use tokens. If a concurrent request has already modified the recovery array, the update fails and the login is rejected. ### Workarounds There are no known workarounds.

How to fix CVE-2026-33624

To remediate CVE-2026-33624, upgrade the affected package to a fixed version below.

• —upgrade to 8.6.60 or later
• —upgrade to 9.6.0-alpha.54 or later

Is CVE-2026-33624 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (2)

• from 0, < 8.6.60, >= 9.0.0, < 9.6.0
• >= 9.0.0, < 9.6.0-alpha.54

CVSS scores

References (7)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-33624
• PATCHgithub.com/parse-community/parse-server
• WEBgithub.com/parse-community/parse-server/commit/5e70094250a36bfcc14ecd49592be2b94fba66ff
• WEBgithub.com/parse-community/parse-server/commit/fc3da35a81d5083b453e8967cabcc880f1a3bd0c