No exploitation reported

CVE-2021-20040

No exploitation reported by the sources we read.

Published2021-12-08
WeaknessCWE-22 · CWE-23

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

A relative path traversal vulnerability in the SMA100 upload funtion allows a remote unauthenticated attacker to upload crafted web pages or files as a 'nobody' user. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

Timeline

dates in UTC

2021-12-0810:15CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

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-2021-20040?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-20040?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Sonicwall sma 200 firmwareversion to verify

Branch	Affected	Fixed in	Source
10.2	= 10.2.0.8-37sv	no fix published	NVD
10.2	= 10.2.1.1-19sv	no fix published	NVD

Sonicwall sma 210 firmwareversion to verify

Branch	Affected	Fixed in	Source
10.2	= 10.2.0.8-37sv	no fix published	NVD
10.2	= 10.2.1.1-19sv	no fix published	NVD

Sonicwall sma 400 firmwareversion to verify

Branch	Affected	Fixed in	Source
10.2	= 10.2.0.8-37sv	no fix published	NVD
10.2	= 10.2.1.1-19sv	no fix published	NVD

2 more products in the sources.

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

Fix

Advisories and patches

psirt.global.sonicwall.comVendor Advisory

Detection

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

Sources

NVDCVSS 3.17.5read 2026-10-23
NVDCVSS 2.05read 2026-10-23
CNAweakness (CWE)CWE-23read 2026-10-23
NVDweakness (CWE)CWE-22read 2026-10-23
FIRST EPSSEPSS score25.2 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Published: 2021-12-08
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-20040?

Is CVE-2021-20040 actively exploited?

Active exploitation of CVE-2021-20040 has not been confirmed. Its EPSS score was 25.2% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-20040?

CVE-2021-20040 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

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