CVE-2023-28121Known exploitationPublic exploitNetwork attack vector

Unauthenticated administrator impersonation via unchecked user header

Published Apr 12, 2023 · Updated Aug 2, 2024

Authentication bypass in Automattic WooPayments 4.8.0 through 5.6.1 allows remote attackers to gain administrator access via HTTP. The Platform_Checkout_Session user filter accepts the numeric X-WCPAY-PLATFORM-CHECKOUT-USER header as the current user ID without authentication or validation. An activated affected plugin lets an unauthenticated request impersonate an existing administrator and create a new administrator account.

CVSS severity9.8
Critical
EPSS probability86.51%
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 Automattic WooPayments 4.8.0 through 5.6.1 allows remote attackers to gain administrator access via HTTP. The Platform_Checkout_Session user filter accepts the numeric X-WCPAY-PLATFORM-CHECKOUT-USER header as the current user ID without authentication or validation. An activated affected plugin lets an unauthenticated request impersonate an existing administrator and create a new administrator account.

The record

CVE
CVE-2023-28121
Published
Apr 12, 2023
Updated
Aug 2, 2024
Vendor
Automattic
Product
WooPayments
Classifications
CWE-287, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2023Exploitation reportedJuly 2023 targeted WooPayments exploitation campaign
  3. Aug 2, 2024Record 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=Fixed version 5.6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Automattic · WooPaymentsversion=Fixed version 5.6.2

Published CVSS scores

9.8NISTCVSS: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 exploitPublished

Weakness, pattern, technique

CWE-287Improper Authentication
T1190Exploit Public-Facing Application

Public exploit references

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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