What is CVE-2021-21911?

CVE-2021-21911 is a high-severity vulnerability in Advantech R-Seenet, classified under Incorrect Default Permissions. CVSS score: 7.8/10. Published 2021-12-22.

How severe is CVE-2021-21911?

High severity. CVSS v3 base score is 7.8 out of 10.

Privilege escalation in Advantech R-Seenet

CVE-2021-21911

A privilege escalation vulnerability exists in the Windows version of installation for Advantech R-SeeNet Advantech R-SeeNet 2.4.15 (30.07.2021). A specially-crafted file can be replaced in the system to escalate privileges to NT SYSTEM authority. An attacker can provide a malicious file to trigger this vulnerability.

Published 2021-12-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (21.8th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Advantech R-Seenet — versions 2.4.15
Microsoft Windows
Advantech — versions Advantech R-SeeNet Advantech R-SeeNet 2.4.15 (30.07.2021)

Weakness classification (CWE)

References

talosintelligence.com/vulnerability_reports/TALOS-2021-1360 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21911?: CVE-2021-21911 is a high-severity vulnerability in Advantech R-Seenet, classified under Incorrect Default Permissions. CVSS score: 7.8/10. Published 2021-12-22.
How severe is CVE-2021-21911?: High severity. CVSS v3 base score is 7.8 out of 10.