CVE-2026-43930
Parse Server: MFA SMS one-time password accepted twice under concurrent login
- State
- Published
- Severity
- 2.1 Low
- Published
- May 12, 2026
- Updated
- May 13, 2026
- Reserved
- May 4, 2026
Description
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 8.6.76 and 9.9.0-alpha.2, a race condition in the MFA SMS one-time password (OTP) login path allows two concurrent /login requests carrying the same OTP to both succeed and both receive valid session tokens, breaking the single-use property of the OTP. The vulnerability requires the attacker to already possess the victim's password and intercept the active SMS OTP (e.g. via SIM swap, network mirror, or phishing relay) and to race the legitimate login request, so the practical attack surface is narrow. This vulnerability is fixed in 8.6.76 and 9.9.0-alpha.2.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 2.1 Low | CVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | GitHub_M |
Weaknesses
- CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Affected Products
| Product | Versions |
|---|---|
parse-serverparse-community |
|
References
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.