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Vulnerability record · CVE-2023-0992 · published 9 June 2023

CVE-2023-0992: Shield Security WordPress plugin stored XSS via User-Agent header

Getshieldsecurity · Shield Security

The Shield Security plugin for WordPress is vulnerable to stored cross-site scripting in versions up to and including 17.0.17. The flaw is reached through the 'User-Agent' header, allowing unauthenticated attackers to inject arbitrary web scripts that execute when a user views an injected page.

6.1 CVSS 3.1 Medium EPSS 93% · top 0.2% CWE-79 · Cross-site scripting
6.1CVSS 3.1 base score
93%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
7References
17 Jun 2026Last modified by NVD

Description

The Shield Security plugin for WordPress is vulnerable to stored Cross-Site Scripting in versions up to, and including, 17.0.17 via the 'User-Agent' header. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 18 September 2026. Confidence: high.

high priorityUnauthenticated injection with a very high EPSS score and a patch available makes timely remediation important, though exploitation requires a victim to view the injected page.

What it is

The Shield Security plugin for WordPress is vulnerable to stored cross-site scripting in versions up to and including 17.0.17. The flaw is reached through the 'User-Agent' header, allowing unauthenticated attackers to inject arbitrary web scripts that execute when a user views an injected page.

Impact

An attacker can run arbitrary script in the context of a victim's browser session, potentially stealing cookies or session tokens and performing actions as the victim. Because the payload is stored, it can affect multiple users over time.

Attack surface

Reachable over the network by sending a crafted User-Agent header; no authentication is required to inject, but a victim must access the injected page for the script to execute (UI:R).

Exploitation

Not listed in CISA KEV and no ransomware usage is documented; EPSS is very high (0.93046, 99.828th percentile), and references include a patch and third-party advisory, indicating public technical detail but no confirmed in-the-wild exploitation in this record.

What to do

  • Update Shield Security to a version newer than 17.0.17 (patch referenced in the plugin changeset).
  • If immediate patching is not possible, disable or remove the plugin until it can be updated.
  • Deploy a web application firewall rule to block or sanitize malicious User-Agent header values.
  • Apply output encoding and input sanitization for any header data rendered in admin or public pages.
  • Review and restrict who can view pages that render logged header data.

Detection

  • Search web server and application logs for User-Agent strings containing script tags or HTML event handlers.
  • Monitor for unexpected JavaScript or HTML appearing in stored header/log data within the WordPress database.
  • Use WAF or IDS signatures to alert on XSS patterns in the User-Agent header.
  • Audit plugin pages that display User-Agent data for signs of injected content.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&new=2883864%40wp-simple-firewall%2Ftrunk&ol Patch
https://wordpress.org/plugins/wp-simple-firewall/#developers Product
https://www.wordfence.com/blog/2023/04/multiple-vulnerabilities-patched-in-shield-security/
https://www.wordfence.com/threat-intel/vulnerabilities/id/162dff28-94ea-4a47-a6cb-a13317cf1a04?source=cve Third Party Advisory
https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&new=2883864%40wp-simple-firewall%2Ftrunk&ol Patch
https://wordpress.org/plugins/wp-simple-firewall/#developers Product
https://www.wordfence.com/threat-intel/vulnerabilities/id/162dff28-94ea-4a47-a6cb-a13317cf1a04?source=cve Third Party Advisory

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2023-0992), CISA KEV, FIRST EPSS (scores of 2026-09-24). This page is refreshed as NVD updates the record.