CVE-2021-20027

mediumpriority · track · 30EPSS 0.013 · 70 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.29% (70th) EPSS

CVSS 5 · medium

Is it mine?

16 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-27

A buffer overflow vulnerability in SonicOS allows a remote attacker to cause a Denial of Service (DoS) by sending a specially crafted request. This vulnerability affects SonicOS Gen5, Gen6, Gen7 platforms, and SonicOSv virtual firewalls.

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-120USprimary

affected products (16)

Products and version ranges known to be affected.

SonicWall SonicOS≤ SonicOS 7.0.1-R1262 and earlierenisa_euvdEU
SonicWall SonicOS≤ SonicOS 5.9.1.13 and earlierenisa_euvdEU
SonicWall SonicOS≤ SonicOS 6.0.5.3 and earlierenisa_euvdEU
SonicWall SonicOS≤ SonicOS 6.5.1.12 and earlierenisa_euvdEU
SonicWall SonicOS≤ SonicOS 6.5.4.7 and earlierenisa_euvdEU
SonicWall SonicOS≤ SonicOS 7.0.1-R514 and earlierenisa_euvdEU
SonicWall SonicOS≤ SonicOSv 6.5.4.4 and earlierenisa_euvdEU
SonicWall SonicOS≤ SonicOS 7.0.1-R1219 and earlierenisa_euvdEU
sonicwall sonicos≤ 5.9.1.13nvdUScpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos≤ 6.0.5.3-94onvdUScpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos≤ 6.5.1.12nvdUScpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos≤ 6.5.4.7nvdUScpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos≤ 7.0.1-r.1219nvdUScpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos≤ 7.0.1-r1262nvdUScpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicos≤ 7.0.1-r514nvdUScpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*
sonicwall sonicosall versionsnvdUScpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2021-06-14modified 2026-06-17

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+5663 more

references (4)

External citations — patches, advisories, analysis.

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