CVE-2026-33624
Parse Server: MFA recovery code single-use bypass via concurrent requests
Description
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to versions 8.6.60 and 9.6.0, 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. This issue has been patched in versions 8.6.60 and 9.6.0
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 0.2%, 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
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N |