No exploitation reportedFix available

CVE-2021-44159

Q: Is CVE-2021-44159 actively exploited?

Active exploitation of CVE-2021-44159 has not been confirmed. Its EPSS score was 3.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-44159?

CVE-2021-44159 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2021-12-20
Fixed in2021-09-16
WeaknessCWE-434

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

4MOSAn GCB Doctor’s file upload function has improper user privilege control. A remote attacker can upload arbitrary files including webshell files without authentication and execute arbitrary code in order to perform arbitrary system operations or deny of service attack.

Timeline

dates in UTC

2021-12-2003:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-44159?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-44159?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

4mosan gcb doctor

Branch	Affected	Fixed in	Source
2021.x	< 2021-09-16	2021-09-16	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update 4mosan gcb doctor to 2021-09-16

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CNACVSS 3.19.8read 2026-10-23
NVDCVSS 2.010read 2026-10-23
CNAweakness (CWE)CWE-434read 2026-10-23
FIRST EPSSEPSS score3.5 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2021-12-20
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-44159?

Is CVE-2021-44159 actively exploited?

Active exploitation of CVE-2021-44159 has not been confirmed. Its EPSS score was 3.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-44159?

CVE-2021-44159 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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