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PatchSiren cyber security CVE debrief

CVE-2021-20035 SonicWall CVE debrief

CVE-2021-20035 is a SonicWall SMA100 Appliances OS command injection vulnerability that CISA added to its Known Exploited Vulnerabilities catalog on 2025-04-16. A KEV listing means the issue is known to be actively exploited, so affected environments should treat it as a high-priority exposure. CISA’s entry directs organizations to apply vendor mitigations, follow BOD 22-01 guidance for cloud services where applicable, or discontinue use of the product if mitigations are unavailable.

Vendor
SonicWall
Product
SMA100 Appliances
CVSS
Unknown
CISA KEV
Listed
Original CVE published
2025-04-16
Original CVE updated
2025-04-16
Advisory published
2025-04-16
Advisory updated
2025-04-16

Who should care

Security teams, appliance administrators, and incident responders responsible for SonicWall SMA100 deployments should prioritize this CVE. It is especially important for internet-exposed remote access or security gateway environments where delay in mitigation can leave a known-exploited path open.

Technical summary

The vulnerability is described as an OS command injection issue in SonicWall SMA100 Appliances. The supplied corpus does not include exploit details, affected versions, or a CVSS score, but the KEV designation confirms active exploitation risk. From a defensive standpoint, command injection in an appliance context can allow unauthorized command execution if the vulnerable path is reachable.

Defensive priority

Critical. CISA has listed the CVE in KEV and set a remediation due date of 2025-05-07, indicating urgent action is expected.

Recommended defensive actions

  • Apply SonicWall mitigations and vendor guidance referenced by CISA as soon as possible.
  • Verify whether any SMA100 appliances are exposed or reachable from untrusted networks.
  • Track CISA BOD 22-01 requirements if the product is used in cloud services.
  • If mitigations are unavailable, discontinue use of the product per CISA guidance.
  • Review related security logs and appliance configuration for signs of suspicious activity around the KEV date.
  • Confirm asset inventory and remediation status before the CISA due date of 2025-05-07.

Evidence notes

All statements are based on the supplied CISA KEV metadata and official reference links. The corpus identifies the issue as 'SonicWall SMA100 Appliances OS Command Injection Vulnerability,' marks it as known exploited, and provides CISA remediation guidance. No CVSS score, affected version range, or exploit mechanics were included in the supplied source material.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-20035 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-20035

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

  • CVE-2021-20035 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-20035

    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.