Medium severity · published May 12, 2026
CVE-2026-43930
Parse Server: MFA SMS one-time password accepted twice under concurrent login
5.9
CVSS
0.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 15% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PA
parse-server · parse-community
>= 9.0.0, < 9.9.0-alpha.2; < 8.6.76 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-43930
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-43930
Issue Tracking
https://github.com/parse-community/parse-server/pull/10448
Issue Tracking
https://github.com/parse-community/parse-server/pull/10449
Mitigation
https://github.com/parse-community/parse-server/security/advisories/GHSA-jpq4-7fmq-q5fj
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