What is CVE-2026-41319?

CVE-2026-41319 is a medium-severity vulnerability in Jstedfast Mailkit, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 6.5/10. Published 2026-04-24.

How severe is CVE-2026-41319?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Jstedfast Mailkit

CVE-2026-41319

MailKit is a cross-platform mail client library built on top of MimeKit. A STARTTLS Response Injection vulnerability in versions prior to 4.16.0 allows a Man-in-the-Middle attacker to inject arbitrary protocol responses across the plaintex…

EPSS: 0.000 (11.6th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.

Affected products

Jstedfast Mailkit — versions < 4.16.0
Mimekit Mailkit

Weakness classification (CWE)

CWE-74 — Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection)

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2026-41319?: CVE-2026-41319 is a medium-severity vulnerability in Jstedfast Mailkit, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 6.5/10. Published 2026-04-24.
How severe is CVE-2026-41319?: Medium severity. CVSS v3 base score is 6.5 out of 10.