CVE-2026-43930

Parse Server: MFA SMS one-time password accepted twice under concurrent login

MEDIUM
5.9
CVSS Score
Published: May 12, 2026 at 01:34 PM UTC
Updated: June 17, 2026 at 10:50 AM UTC
2 products affected across 2 vendorsParse ServerParse Server

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Severity
MEDIUM5.9
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 8.6.769.0.0 ≤ v < 9.9.09.9.0 alpha1
v < 8.6.76v < 9.9.0-alpha.2
Affected range stops below 8.6.76, so it looks safe — our inference, not a vendor statement
Affected range stops below 9.9.0-alpha.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

x_refsource_CONFIRMMitigationVendor Advisory
Source: cverecord
https://github.com/parse-community/parse-server/security/advisories/GHSA-jpq4-7fmq-q5fj
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/parse-community/parse-server/pull/10448
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/parse-community/parse-server/pull/10449

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-362

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