CVE-2021-4387Public exploitNetwork attack vector

Featured-property changes via missing nonce validation

Published Jul 1, 2023 · Updated Apr 8, 2026

Cross-site request forgery in WPOpal Opal Estate 1.6.11 and earlier allows remote attackers to set or remove featured properties. The opalestate_set_feature_property() and opalestate_remove_feature_property() functions process state-changing requests without valid nonce verification. Exploitation requires a site administrator to follow or activate a forged request, and the established consequence is limited to changing featured-property status.

CVSS severity4.3
Medium
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in WPOpal Opal Estate 1.6.11 and earlier allows remote attackers to set or remove featured properties. The opalestate_set_feature_property() and opalestate_remove_feature_property() functions process state-changing requests without valid nonce verification. Exploitation requires a site administrator to follow or activate a forged request, and the established consequence is limited to changing featured-property status.

The record

CVE
CVE-2021-4387
Published
Jul 1, 2023
Updated
Apr 8, 2026
Vendor
WPOpal
Product
Opal Estate
Classifications
CWE-352, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 1, 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 <=1.6.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

WPOpal · Opal Estateversion=0 <=1.6.11

Published CVSS scores

4.3WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/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.

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-352Cross-Site Request Forgery (CSRF)
T1189Drive-by Compromise

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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