Vulnerability in Contact Form By Supsystic

CVE-2026-115303

The Contact Form by Supsystic WordPress plugin before 1.11.1 does not strip CR/LF characters or re-validate submitted field values before concatenating them into outgoing email headers when a form is configured to map a submitted field into its Reply-To, From or Cc header, allowing unauthenticated users to inject arbitrary email headers such as additional Bcc or Cc recipients into the notification email.

Vulnerability class: CRLF Injection

Published · last modified .

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (13.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 13.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

The 30-day trend appears once there are two daily scores.

Affected products

  • Contact Form By Supsystic

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-115303?
CVE-2026-115303 is a low-severity vulnerability in Contact Form By Supsystic, classified under CRLF Injection. CVSS score: 3.7/10. Published 2026-10-29.
How severe is CVE-2026-115303?
Low severity. CVSS v3 base score is 3.7 out of 10.