What is CVE-2020-35609?

CVE-2020-35609 is a medium-severity vulnerability in Microsoft Azure Sphere, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 5.5/10. Published 2020-12-22.

How severe is CVE-2020-35609?

Medium severity. CVSS v3 base score is 5.5 out of 10.

Vulnerability in Microsoft Azure Sphere

CVE-2020-35609

A denial-of-service vulnerability exists in the asynchronous ioctl functionality of Microsoft Azure Sphere 20.05. A sequence of specially crafted ioctl calls can cause a denial of service. An attacker can write shellcode to trigger this vulnerability.

Published 2020-12-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.013 (70.1th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 70.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.013 · change: +0.000

Affected products

Microsoft Azure Sphere — versions 20.05

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

www.talosintelligence.com/vulnerability_reports/TALOS-2020-1117 (Exploit, Third Party Advisory)
talosintelligence.com/vulnerability_reports/TALOS-2020-1117 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2020-35609?: CVE-2020-35609 is a medium-severity vulnerability in Microsoft Azure Sphere, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 5.5/10. Published 2020-12-22.
How severe is CVE-2020-35609?: Medium severity. CVSS v3 base score is 5.5 out of 10.