CVE-2026-83625 supsysticcom CVE debrief

Who should care

Defenders responsible for WordPress installations using the Contact Form by Supsystic plugin, especially if the plugin version is 1.10.2 or earlier, should assess exposure and prioritize verification of IP Address Header injection risk.

Why it matters

The Contact Form by Supsystic plugin for WordPress is vulnerable to Stored Cross-Site Scripting via IP Address Header, allowing unauthenticated attackers to inject arbitrary web scripts. Defenders should prioritize verifying exposure and implementing input sanitization and output escaping for IP Address Header.

• Risk of arbitrary web script injection in WordPress pages
• Potential for unauthenticated attackers to inject malicious payloads
• Need for input sanitization and output escaping for IP Address Header
• Verification priority for WordPress installations using Contact Form by Supsystic plugin

Technical summary

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. This is due to insufficient input sanitization and output escaping, allowing unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The vulnerability can be exploited by first calling the 'updateNonce' action to obtain a valid nonce, then submitting a contact form with a malicious payload in a spoofed IP header such as X-Forwarded-For.

Defensive priority

Defenders should prioritize verifying exposure of WordPress installations using the Contact Form by Supsystic plugin, especially if the plugin version is 1.10.2 or earlier, and assess the risk of arbitrary web script injection.

Recommended defensive actions

• Verify WordPress installations for the Contact Form by Supsystic plugin version 1.10.2 or earlier
• Assess exposure to IP Address Header injection
• Implement input sanitization and output escaping for IP Address Header
• Monitor for suspicious activity on WordPress installations
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and references to source code. The vulnerability was reported by [email protected]. The CVE record was published on 2026-09-05T08:16:40.857Z and has not been modified since then. The NVD entry provides additional information on the vulnerability, including its CVSS score and severity.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.