What is CVE-2021-26264?

CVE-2021-26264 is a medium-severity vulnerability in Emerson Deltav Distributed Control System, classified under Missing Authentication for Critical Function. CVSS score: 6.1/10. Published 2022-01-28.

How severe is CVE-2021-26264?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Auth bypass in Emerson Deltav Distributed Control System

CVE-2021-26264

A specially crafted script could cause the DeltaV Distributed Control System Controllers (All Versions) to restart and cause a denial-of-service condition.

Vulnerability class: Broken Authentication

Published 2022-01-28 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.002 (7.5th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 7th percentile — 7.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

www.cisa.gov/uscert/ics/advisories/icsa-21-355-04 (US Government Resource, Third Party Advisory, Mitigation)

Frequently asked questions

What is CVE-2021-26264?: CVE-2021-26264 is a medium-severity vulnerability in Emerson Deltav Distributed Control System, classified under Missing Authentication for Critical Function. CVSS score: 6.1/10. Published 2022-01-28.
How severe is CVE-2021-26264?: Medium severity. CVSS v3 base score is 6.1 out of 10.