CVE-2026-43930: CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') in parse-community parse-server
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, 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.
AI Analysis
Technical Summary
Parse Server versions before 8.6.76 and 9.9.0-alpha.2 contain a race condition in the multi-factor authentication SMS OTP login flow. Specifically, two concurrent /login requests with the same OTP can both succeed, resulting in multiple valid session tokens from a single OTP. This breaks the single-use guarantee of the OTP mechanism. Successful exploitation requires possession of the victim's password and interception of the SMS OTP, such as via SIM swap or phishing relay. The issue is addressed in the specified patched versions.
Potential Impact
The vulnerability allows an attacker who already has the victim's password and has intercepted the SMS OTP to reuse the OTP concurrently, gaining multiple valid session tokens. This undermines the security of the MFA SMS OTP mechanism by allowing multiple logins with a single OTP. However, the attack requires significant preconditions, limiting its practical impact.
Mitigation Recommendations
Upgrade parse-server to version 8.6.76 or later, or 9.9.0-alpha.2 or later, where this race condition is fixed. No other mitigation is indicated. Patch status is confirmed by the vendor's versioning information.
CVE-2026-43930: CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') in parse-community parse-server
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, 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.
CVSS v4.0
Score 2.1low
Affected software
parse-community
parse-server
pkg:github/parse-community/parse-serverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
Parse Server versions before 8.6.76 and 9.9.0-alpha.2 contain a race condition in the multi-factor authentication SMS OTP login flow. Specifically, two concurrent /login requests with the same OTP can both succeed, resulting in multiple valid session tokens from a single OTP. This breaks the single-use guarantee of the OTP mechanism. Successful exploitation requires possession of the victim's password and interception of the SMS OTP, such as via SIM swap or phishing relay. The issue is addressed in the specified patched versions.
Potential Impact
The vulnerability allows an attacker who already has the victim's password and has intercepted the SMS OTP to reuse the OTP concurrently, gaining multiple valid session tokens. This undermines the security of the MFA SMS OTP mechanism by allowing multiple logins with a single OTP. However, the attack requires significant preconditions, limiting its practical impact.
Mitigation Recommendations
Upgrade parse-server to version 8.6.76 or later, or 9.9.0-alpha.2 or later, where this race condition is fixed. No other mitigation is indicated. Patch status is confirmed by the vendor's versioning information.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-05-04T16:59:09.089Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a0333e5cbff5d8610ef1d3e
Added to database: 05/12/2026, 14:06:29 UTC
Last enriched: 05/19/2026, 18:46:21 UTC
Last updated: 09/15/2026, 10:01:32 UTC
Views: 113
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