CVE-2021-20035
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.
do firstApply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Can a WAF block it? Partly. OS command injection puts shell syntax into the request. WAF rules catch common shell commands but miss encoded or unusual payloads.
Also consider: shlex/execve-style APIs
Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2021-20035 being exploited?
Yes. CVE-2021-20035 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2021-20035?
CVE-2021-20035 is rated Medium with a CVSS score of 6.5. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2021-20035?
Yes. A fix has been recorded for CVE-2021-20035. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2021-20035 affect?
CVE-2021-20035 affects sonicwall:sma_200_firmware, sonicwall:sma_210_firmware, sonicwall:sma_400_firmware, sonicwall:sma_410_firmware, and 1 further product or version. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
- affected9.0.0.10-28sv and earlier
- affected10.2.0.7-34sv and earlier
- affected10.2.1.0-17sv and earlier
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
cisa ssvc
- exploitation
- active
- automatable
- no
- technical impact
- total
Assessed by CISA 17 Apr 2025 (SSVC 2.0.3).
timeline
- 27 Sept 2021Published
- 16 Apr 2025Added to CISA KEV (exploited in the wild) · 1,296 days (about 4 years) later
- 17 Apr 2025CISA SSVC assessment: exploitation active · 1 day later
- 7 May 2025CISA remediation due date (US federal agencies) · 20 days later
- 21 Oct 2025CVE record last updated · 168 days (about 6 months) later
- 2 Nov 2026Analysed by vulneraibility.com · 377 days (about 1 year) later
- Linkpsirt.global.sonicwall.com /vuln-detail/SNWLID-2021-0022
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-20035
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.