What is CVE-2021-39363?

CVE-2021-39363 is a critical-severity vulnerability in Honeywell Hbw2per1, classified under Command Injection. CVSS score: 9.8/10. Published 2022-02-24.

How severe is CVE-2021-39363?

Critical severity. CVSS v3 base score is 9.8 out of 10.

RCE in Honeywell Hbw2per1

CVE-2021-39363

Honeywell HDZP252DI 1.00.HW02.4 and HBW2PER1 1.000.HW01.3 devices allow a video replay attack after ARP cache poisoning has been achieved.

Vulnerability class: Command Injection (OS Command Injection)

Published 2022-02-24 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.014 (71.7th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 71.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000

Affected products

Honeywell Hbw2per1
Honeywell Hbw2per1 Firmware — versions 1.000.hw01.3
Honeywell Hdzp252di
Honeywell Hdzp252di Firmware — versions 1.00.hw02.4

Weakness classification (CWE)

CWE-77 — Command Injection

References

www.honeywell.com/us/en/product-security (Vendor Advisory)
buildings.honeywell.com/us/en/brands/our-brands/security/support-and-resources/… (Vendor Advisory)
buildings.honeywell.com/content/dam/hbtbt/en/documents/downloads/Security_Notif… (Vendor Advisory)

Frequently asked questions

What is CVE-2021-39363?: CVE-2021-39363 is a critical-severity vulnerability in Honeywell Hbw2per1, classified under Command Injection. CVSS score: 9.8/10. Published 2022-02-24.
How severe is CVE-2021-39363?: Critical severity. CVSS v3 base score is 9.8 out of 10.