CVE-2023-2734Known exploitationNetwork attack vector

Account takeover via unverified cart-sync user ID

Published May 25, 2023 · Updated Apr 8, 2026

Authentication bypass in FluxBuilder MStore API 3.9.1 and earlier allows remote attackers to impersonate any user via mobile cart sync. The cart-sync handler trusts a requester-supplied user ID without verifying that it belongs to an authenticated requester, then establishes that user context. Knowing a valid user ID is enough to obtain that account's privileges, including administrator control when an administrator ID is supplied.

CVSS severity9.8
Critical
EPSS probability3.81%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in FluxBuilder MStore API 3.9.1 and earlier allows remote attackers to impersonate any user via mobile cart sync. The cart-sync handler trusts a requester-supplied user ID without verifying that it belongs to an authenticated requester, then establishes that user context. Knowing a valid user ID is enough to obtain that account's privileges, including administrator control when an administrator ID is supplied.

The record

CVE
CVE-2023-2734
Published
May 25, 2023
Updated
Apr 8, 2026
Vendor
FluxBuilder
Product
MStore API
Classifications
CWE-288, T1078
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 25, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=3.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FluxBuilder · MStore APIversion=0 <=3.9.1

Published CVSS scores

9.8WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-288Authentication Bypass Using an Alternate Path or Channel
T1078Valid Accounts

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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