CVE-2021-43409Public exploitNetwork attack vector

Administrator account takeover via unsanitized OpenID errors

Published Nov 19, 2021 · Updated Sep 17, 2024

Stored XSS in WPO365 | LOGIN 15.3 and earlier allows remote attackers to run scripts in an administrator's browser via an OpenID error. ServicesRouter_Service.php passes the error_description POST value to Log_Service::write_log without sanitization, and the dashboard later renders the stored log entry. Submission requires no authentication, but execution requires an administrator to access the affected WPO365 page; the script can act with that administrator's privileges.

CVSS severity9.3
Critical
EPSS probability0.97%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in WPO365 | LOGIN 15.3 and earlier allows remote attackers to run scripts in an administrator's browser via an OpenID error. ServicesRouter_Service.php passes the error_description POST value to Log_Service::write_log without sanitization, and the dashboard later renders the stored log entry. Submission requires no authentication, but execution requires an administrator to access the affected WPO365 page; the script can act with that administrator's privileges.

The record

CVE
CVE-2021-43409
Published
Nov 19, 2021
Updated
Sep 17, 2024
Vendor
WPO365
Product
WPO365 | LOGIN
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=unspecified <15.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WPO365 · WPO365 | LOGINversion=unspecified <15.3

Published CVSS scores

9.3AppCheck Ltd.CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007JavaScript/JScript

Public exploit references

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

Technologies

Your stack

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Your stack

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