Home/CVE/An unauthenticated and remote adversary can consume all of the device's CPU due to crafted HTTP requests sent to SMA100
CVE

CVE-2021-20041

An unauthenticated and remote adversary can consume all of the device's CPU due to crafted HTTP requests sent to SMA100

An unauthenticated and remote adversary can consume all of the device's CPU due to crafted HTTP requests sent to SMA100 /fileshare/sonicfiles/sonicfiles resulting in a loop with unreachable exit condition. This vulnerability affected SMA 200, 210, 400, 410 and 500v appliances.

HIGH · CVSS 7.5 EPSS 0.01317
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
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Affected Products & Versions

5
sonicwall sma 200 firmwareall versions
sonicwall sma 210 firmwareall versions
sonicwall sma 410 firmwareall versions
sonicwall sma 400 firmwareall versions
sonicwall sma 500v firmwareall versions
◈

Detection Rules (IDS/IPS)

1
et-openET WEB_SERVER SonicWall SMA Unauthenticated sonicfiles CPU Exhaustion (CVE-2021-20041)web-application-attack
Open rulesets (ET Open, Snort Community, abuse.ch) link to source. Commercial rulesets are reference-only.
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · PSIRT@sonicwall.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD08 Dec 2021 · 10:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0026Vendor Advisory
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