What is CVE-2021-43270?

CVE-2021-43270 is a high-severity vulnerability in Datalust Seq.app.emailplus, classified under Cleartext Transmission of Sensitive Information. CVSS score: 7.5/10. Published 2021-11-02.

How severe is CVE-2021-43270?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Datalust Seq.app.emailplus

CVE-2021-43270

Datalust Seq.App.EmailPlus (aka seq-app-htmlemail) 3.1.0-dev-00148, 3.1.0-dev-00170, and 3.1.0-dev-00176 can use cleartext SMTP on port 25 in some cases where encryption on port 465 was intended.

Published 2021-11-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.004 (29.5th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 29.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Datalust Seq.app.emailplus — versions 3.1.0

Weakness classification (CWE)

CWE-319 — Cleartext Transmission of Sensitive Information

References

github.com/datalust/seq-app-htmlemail/pull/93 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-43270?: CVE-2021-43270 is a high-severity vulnerability in Datalust Seq.app.emailplus, classified under Cleartext Transmission of Sensitive Information. CVSS score: 7.5/10. Published 2021-11-02.
How severe is CVE-2021-43270?: High severity. CVSS v3 base score is 7.5 out of 10.