Raw vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:NSummary
CVE-2021-20023 is a medium-severity Path Traversal (CWE-22) vulnerability in Sonicwall Email Security. Its CVSS base score is 4.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
SonicWall Email Security version 10.0.9.x is affected by a path traversal vulnerability tracked as CVE-2021-20023 and CWE-22. The flaw permits a post-authenticated attacker to read arbitrary files on the remote host. It carries a CVSS 3.1 base score of 4.9, reflecting network attack vector, low attack complexity, high privileges required, and high confidentiality impact with no integrity or availability effects.
An attacker who has already obtained administrative credentials can send specially crafted requests to the affected Email Security appliance and retrieve sensitive files stored on the system. Because the vulnerability requires authentication, it is primarily a risk to organizations whose management interfaces are reachable from untrusted networks or where credential compromise has already occurred.
The official SonicWall PSIRT advisory SNWLID-2021-0010 addresses the issue, and the vulnerability appears in CISA's catalog of known exploited vulnerabilities, confirming observed in-the-wild activity. Organizations should apply the patches or configuration changes recommended in the vendor advisory and restrict management access to trusted networks.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-7486
Vulnerability Data
SonicWall Email Security version 10.0.9.x contains a vulnerability that allows a post-authenticated attacker to read an arbitrary file on the remote host.
- CWE(s)
- KEV Date Added
- 03 November 2021
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.3.2
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Validates pathnames and filenames to prevent traversal outside intended directories.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.
PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches path traversal via static/dynamic analysis.
Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.
Application security requirements include rules for safe file handling and canonicalization.
Secure architecture principles require least-privilege file access and directory isolation.
Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.
Information access restriction limits which files an application may read or write.