What is CVE-2022-40870?

CVE-2022-40870 is a high-severity vulnerability in Parallels Remote Application Server, classified under Improper Encoding or Escaping of Output. CVSS score: 8.1/10. Published 2022-11-23.

How severe is CVE-2022-40870?

High severity. CVSS v3 base score is 8.1 out of 10.

Vulnerability in Parallels Remote Application Server

CVE-2022-40870

The Web Client of Parallels Remote Application Server v18.0 is vulnerable to Host Header Injection attacks. This vulnerability allows attackers to execute arbitrary commands via a crafted payload injected into the Host header.

Published 2022-11-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.021 (80.7th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 81st percentile — 80.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.019 · newest: 0.021 · change: +0.001

Affected products

Parallels Remote Application Server — versions 18.0

Weakness classification (CWE)

CWE-116 — Improper Encoding or Escaping of Output

References

github.com/IthacaLabs/Parallels/tree/main/ParallelsRemoteApplicationServer (Exploit, Third Party Advisory)
github.com/IthacaLabs/Parallels/blob/main/ParallelsRemoteApplicationServer/HHI_… (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2022-40870?: CVE-2022-40870 is a high-severity vulnerability in Parallels Remote Application Server, classified under Improper Encoding or Escaping of Output. CVSS score: 8.1/10. Published 2022-11-23.
How severe is CVE-2022-40870?: High severity. CVSS v3 base score is 8.1 out of 10.