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PatchSiren cyber security CVE debrief

CVE-2021-20023 SonicWall CVE debrief

CVE-2021-20023 is a SonicWall Email Security path traversal vulnerability that CISA added to its Known Exploited Vulnerabilities catalog on 2021-11-03. CISA also marks it as having known ransomware campaign use and directs affected organizations to apply vendor updates, so any unpatched deployment should be treated as an urgent remediation item.

Vendor
SonicWall
Product
SonicWall Email Security
CVSS
MEDIUM 4.9
CISA KEV
Listed
Original CVE published
2021-11-03
Original CVE updated
2021-11-03
Advisory published
2021-11-03
Advisory updated
2021-11-03

Who should care

Security and IT teams responsible for SonicWall Email Security, especially vulnerability management, email security, and incident response staff. Organizations with externally exposed or broadly deployed SonicWall Email Security instances should prioritize this issue.

Technical summary

The supplied sources identify this CVE as a path traversal flaw in SonicWall Email Security. CISA’s KEV entry indicates known exploitation and known ransomware campaign use, and the prescribed action is to apply updates per vendor instructions.

Defensive priority

Immediate

Recommended defensive actions

  • Inventory all SonicWall Email Security deployments and confirm whether any instances are still exposed or unpatched.
  • Apply vendor updates per the guidance referenced by CISA as soon as possible.
  • Treat any still-unpatched deployment as an urgent remediation priority because this CVE is in CISA’s KEV catalog and has known ransomware campaign use.
  • Verify remediation against the current CISA KEV catalog and internal asset records.

Evidence notes

CISA’s KEV record for CVE-2021-20023 names the issue as the SonicWall Email Security Path Traversal Vulnerability, records it on 2021-11-03, and notes known ransomware campaign use with the required action to apply updates per vendor instructions. The official CVE record and NVD entry are included as reference links, but the supplied corpus does not provide a CVSS score.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-20023 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-20023

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-20023 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-20023

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.