Security readout for executives and security teams
Plain-English summary
SonicWall Email Security 10.0.9 and earlier contains a critical flaw that can let an unauthenticated attacker create an administrator account through a crafted HTTP request. That means an exposed appliance could be taken over without credentials, with high impact to confidentiality, integrity, and availability.
Executive priority
Treat this as urgent if SonicWall Email Security is present. The vulnerability is critical, remotely reachable, needs no credentials, and is listed by CISA as known exploited. Internet-facing systems should be identified and remediated first.
Technical view
CVE-2021-20021 is a CWE-269 improper privilege management issue in SonicWall Email Security 10.0.9 and earlier. The CVSS 3.1 score is 9.8, with network access, low complexity, no privileges, and no user interaction required. CISA lists it in KEV, supporting known exploitation.
Likely exposure
Exposure is most likely where SonicWall Email Security 10.0.9 or earlier is reachable over a network, especially from the internet. The source bundle does not identify specific deployment modes beyond the affected product and version range.
Exploitation context
Active exploitation is supported by CISA KEV listing. The public description says exploitation involves sending a crafted HTTP request to create an administrative account, but the provided sources do not include operational details, exploit maturity, or attacker tooling specifics.
Researcher notes
The bundle supports critical severity, affected version range, CWE-269 classification, and KEV status. It does not provide fixed-version details, indicators of compromise, or safe validation probes. Avoid assuming specific patches or compromise artifacts beyond vendor and CISA guidance.
Mitigation direction
- Inventory SonicWall Email Security deployments and identify versions 10.0.9 or earlier.
- Check SonicWall PSIRT guidance for the fixed release or vendor-approved remediation.
- Prioritize remediation for any internet-reachable Email Security instance.
- Review administrative accounts for unauthorized creation or unexpected privilege changes.
- Preserve relevant logs before making major recovery changes.
Validation and detection
- Confirm product name and version on each SonicWall Email Security deployment.
- Verify whether the system is reachable from untrusted networks.
- Check administrative account history for unknown or recently created accounts.
- Review HTTP access and application logs for suspicious account-management activity.
- Confirm remediation status against SonicWall PSIRT guidance.
Public sources used
Michael Williams reviewed this cited source version on .
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-269: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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-2021-20021 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2021-0007CVE reference · x_refsource_CONFIRM
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20021CVE 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 Privilege Management
Improper Privilege Management represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.