CVE-2026-115303

Contact Form by Supsystic <= 1.11.0 - Unauthenticated Arbitrary Email Header Injection

2026-10-26 00:00

Strategic Overview

Status: Patched in 1.11.1
Affected Plugin: Contact Form by Supsystic – Drag & Drop Form Builder with Templates & Form Statistics
Affected Version: <= 1.11.0
CVSS: 5.3Medium
Weakness type: CWE-93 · Improper Neutralization of CRLF Sequences
CVE: CVE-2026-115303

View all Contact Form by Supsystic – Drag & Drop Form Builder with Templates & Form Statistics vulnerabilities

At a glance

CVE-2026-115303 is a medium-severity Improper Neutralization of CRLF Sequences vulnerability in the Contact Form by Supsystic WordPress plugin, affecting versions <= 1.11.0. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.11.1; sites on affected versions should update now. Disclosed October 2026, reported by Emirhan Sevmez.

Vulnerability Overview

The Contact Form by Supsystic plugin for WordPress is vulnerable to Email Header Injection in all versions up to, and including, 1.11.0. This is due to missing sanitization of CR/LF characters in user-controlled field values before concatenating them into outgoing email headers via utilsCfs::replaceVariables(). This makes it possible for unauthenticated attackers to inject arbitrary email headers, such as additional Bcc or Cc recipients, into outgoing notification emails sent by any configured contact form. A form must be configured to map a submitted field value into the Reply-To, From, or Cc email header.

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-93: Improper Neutralization of CRLF Sequences

The product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.

Remediation

Update to version 1.11.1, or a newer patched version

How does WordSec protect against this?

This one needs no account at all, which puts it outside what login hardening can reach; WordSec's login security narrows the account-level paths around it, and the firewall is what inspects the request itself. None of that substitutes for the fix: Contact Form by Supsystic 1.11.1 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-115303 https://www.wordfence.com/threat-intel/vulnerabilities/id/b754bab8-a16f-41f0-a3c9-2adc0f572c97 https://nvd.nist.gov/vuln/detail/CVE-2026-115303

Related records

Other vulnerabilities in Contact Form by Supsystic – Drag & Drop Form Builder with Templates & Form Statistics

CVSS Vector

5.3

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityLow
AvailabilityNone

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