CVE-2021-20035
RCE in Sonicwall Sma 200 Firmware ≤ 9.0.0.11-31sv
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2021-20035 is a medium-severity OS Command Injection (CWE-78) vulnerability in Sonicwall Sma 200 Firmware. Its CVSS base score is 6.5 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique NTDS (T1003.003); ranked in the top 9% 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.
CVE-2021-20035 is an OS command injection vulnerability (CWE-78) stemming from improper neutralization of special elements in the management interface of SonicWall SMA 100 appliances. The flaw permits execution of arbitrary commands under the 'nobody' account and carries a CVSS 3.1 score of 6.5 reflecting network attack vector, low complexity, and high availability impact with no confidentiality or integrity effects.
A remote attacker who has already authenticated to the SMA 100 interface can exploit the weakness without user interaction to inject commands that result in denial of service. The attack requires only low-privileged credentials and does not need additional privileges or special network positioning beyond normal management access.
SonicWall advisory SNWLID-2021-0022 and the CISA Known Exploited Vulnerabilities catalog both reference the issue, confirming its inclusion in the CISA catalog of vulnerabilities observed in active exploitation.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-7498
Vulnerability Data
Improper neutralization of special elements in the SMA100 management interface allows a remote authenticated attacker to inject arbitrary commands as a 'nobody' user which potentially leads to DoS.
- CWE(s)
- KEV Date Added
- 16 April 2025
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V1.2.5V1.2.8
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.
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.
PR.PS-06's SDLC practices directly require secure coding and input handling that blocks command-injection defects, yet the single broad outcome leaves many specific neutralization vectors and verification gaps unaddressed.
Routine patching/maintenance can remediate known command-injection CVEs in dependencies (partial forward) but does nothing to stop developers from introducing improper neutralization in custom code (none reverse).
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.