CVE-2026-43930: CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') in parse-community parse-server
A race condition vulnerability exists in parse-community's parse-server prior to versions 8.6.76 and 9.9.0-alpha.2. This flaw allows two concurrent login requests using the same SMS one-time password (OTP) to both succeed, violating the intended single-use property of the OTP. Exploitation requires the attacker to already know the victim's password and intercept the active SMS OTP, making the practical attack surface narrow. The vulnerability is fixed in versions 8.6.
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
A race condition vulnerability exists in parse-community's parse-server prior to versions 8.6.76 and 9.9.0-alpha.2. This flaw allows two concurrent login requests using the same SMS one-time password (OTP) to both succeed, violating the intended single-use property of the OTP. Exploitation requires the attacker to already know the victim's password and intercept the active SMS OTP, making the practical attack surface narrow. The vulnerability is fixed in versions 8.6.
CVSS v4.0
Score 2.1low
Affected software
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
- Remediation Level
- null
Threat ID: 6a0333e5cbff5d8610ef1d3e
Added to database: 05/12/2026, 14:06:29 UTC
Last enriched: 05/19/2026, 18:46:21 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 86
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