Security readout for executives and security teams
Plain-English summary
SonicWall Email Security 10.0.9 and earlier has a high-severity flaw that can let an authenticated attacker upload arbitrary files to the server. Because CISA lists this CVE in KEV, treat exposed or legacy systems as urgent to identify and remediate.
Executive priority
High priority. This affects an email security platform, has high potential impact, and is listed by CISA as known exploited. Confirm exposure quickly and remediate affected systems under change control.
Technical view
CVE-2021-20022 is a CWE-434 unrestricted file upload issue in SonicWall Email Security. The CVSS 3.1 score is 7.2 with network access, low complexity, high privileges required, no user interaction, and high confidentiality, integrity, and availability impact.
Likely exposure
Organizations running SonicWall Email Security 10.0.9 or earlier are in scope. Exposure depends on whether the appliance is reachable by attackers and whether attacker credentials or privileged access are available.
Exploitation context
Active exploitation is supported by CISA KEV listing for CVE-2021-20022. The provided sources do not describe exploit chains, observed campaign details, or exact attacker behavior beyond arbitrary file upload after authentication.
Researcher notes
The source bundle confirms affected product, version range, CWE, CVSS vector, and KEV status. It does not provide patch version details, exploitation mechanics, indicators of compromise, or workaround specifics, so validation should stay focused on versioning, access exposure, and vendor guidance.
Mitigation direction
- Inventory SonicWall Email Security deployments and record exact versions.
- Prioritize any instance running 10.0.9 or earlier.
- Review SonicWall advisory SNWLID-2021-0008 for approved remediation guidance.
- Upgrade or otherwise remediate according to SonicWall guidance.
- Restrict administrative access to trusted networks and accounts.
Validation and detection
- Confirm whether SonicWall Email Security is deployed.
- Check product version against 10.0.9 and earlier.
- Review authentication logs for unusual privileged access.
- Review file integrity or upload records for unexpected files.
- Verify remediation status against SonicWall advisory guidance.
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-434: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection 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 lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-20022 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
- High
- CVSS
- 7.2 (3.1)
- Known Exploited
- Yes
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/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:H/UI:N/S:U/C:H/I:H/A:H1.25.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.2HighVector: CVSS:3.1/AV:N/AC:L/PR:H/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-2021-0008CVE reference · x_refsource_CONFIRM
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20022CVE 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.
Unrestricted Upload of File with Dangerous Type
Unrestricted Upload of File with Dangerous Type represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.