CVE-2026-83625

Contact Form by Supsystic <= 1.10.2 - Unauthenticated Stored Cross-Site Scripting via IP Address Header

2026-09-04 19:31
andrea bocchetti

Strategic Overview

Status
Patched in 1.10.3
Affected Plugin
Contact Form by Supsystic
Affected Version
<= 1.10.2
CVSS
7.2High
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2026-83625
View all Contact Form by Supsystic vulnerabilities

At a glance

CVE-2026-83625 is a high-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Contact Form by Supsystic WordPress plugin, affecting versions <= 1.10.2. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.10.3; sites on affected versions should update now. Disclosed September 2026, reported by andrea bocchetti.

Vulnerability Overview

The Contact Form by Supsystic plugin for WordPress is vulnerable to Stored Cross-Site Scripting via IP Address Header in all versions up to, and including, 1.10.2 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. An unauthenticated attacker can first call the 'updateNonce' action — which is accessible without authentication due to its absence from the plugin's permission list — to obtain a valid nonce, then submit a contact form with a malicious payload in a spoofed IP header such as X-Forwarded-For.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Contact Form by Supsystic <= 1.10.2 carries this weakness at updateNonce, and reaching it takes no account at all. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For Contact Form by Supsystic the fix is 1.10.3: builds <= 1.10.2 are affected, anything from 1.10.3 onward is not.

Remediation

Update to version 1.10.3, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Contact Form by Supsystic 1.10.3 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-83625https://www.wordfence.com/threat-intel/vulnerabilities/id/aa65bced-a449-4ba5-accf-40a824ee464dhttps://nvd.nist.gov/vuln/detail/CVE-2026-83625

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C