Security readout for executives and security teams
Plain-English summary
CVE-2021-20035 affects SonicWall SMA100 appliances. An authenticated remote user can inject commands through the management interface, running as the low-privilege 'nobody' user and potentially causing denial of service. CISA lists it in KEV, so treat exposed SMA100 systems as urgent even though the CVSS rating is medium.
Executive priority
Prioritize remediation for any internet-reachable SMA100 appliance. The business risk is service disruption on a security access appliance, amplified by CISA KEV status. Authentication is required, but compromised or overbroad admin access can make that barrier weak.
Technical view
The issue is CWE-78 command injection in the SMA100 management interface. The CVSS vector is network-accessible, low complexity, low privileges required, no user interaction, unchanged scope, and high availability impact. Affected versions listed are 9.0.0.10-28sv and earlier, 10.2.0.7-34sv and earlier, and 10.2.1.0-17sv and earlier.
Likely exposure
Exposure is most likely where SonicWall SMA100 management interfaces are reachable by authenticated users, especially from the internet or broad internal networks. The source bundle does not identify other SonicWall product lines as affected.
Exploitation context
CISA KEV inclusion supports known exploitation in the wild. The provided CVE data says exploitation requires authentication and can lead to denial of service, not confirmed data theft or privilege escalation.
Researcher notes
Evidence supports authenticated command injection with availability impact as the primary consequence. The source bundle does not provide exploit mechanics, indicators of compromise, or specific fixed-version numbers, so validation should focus on version exposure, management-plane reachability, and vendor advisory confirmation.
Mitigation direction
- Inventory all SonicWall SMA100 appliances and firmware versions.
- Check SonicWall advisory SNWLID-2021-0022 for fixed firmware and upgrade guidance.
- Restrict SMA100 management access to trusted administrative networks only.
- Review administrative accounts and remove unnecessary access.
- Monitor SMA100 availability and management-login activity for anomalies.
Validation and detection
- Confirm whether each SMA100 runs an affected listed version.
- Verify whether the management interface is externally reachable.
- Review CISA KEV status for required remediation urgency.
- Check SonicWall PSIRT guidance before declaring remediation complete.
- Look for unusual authenticated management activity or service disruptions.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-78: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-20035 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CISA KEV status
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H2.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0022CVE reference · x_refsource_CONFIRM
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20035CVE reference · government-resource
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.