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Vulnerabilities

Vulnerability · CVE-2021-20031

A Host Header Redirection vulnerability in SonicOS potentially allows a remote attacker to redirect firewall management users to arbitrary web domains.

Published Oct 12, 2021 · catalog updated Jun 17, 2026 · A Host Header Redirection

Last checked Nov 8, 2026. A connected source was read within the last 7 days.

Check this week

CVE-2021-20031 is not in CISA KEV. FIRST estimates a 12.98% chance of exploitation in the next 30 days. Check whether you run A Host Header Redirection.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A Host Header Redirection).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.1
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
12.98%
Remediation
Version ranges on file
Affected products
cpe sonicwall/sonicos

A Host Header Redirection vulnerability in SonicOS potentially allows a remote attacker to redirect firewall management users to arbitrary web domains.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe sonicwall/sonicos<= 6.0.5.3-94o
  • cpe sonicwall/sonicos<= 6.5.1.12
  • cpe sonicwall/sonicos<= 6.5.4.7
  • cpe sonicwall/sonicos<= 7.0.1-r1262
  • cpe sonicwall/sonicos<= 7.0.1-r1283
  • cpe sonicwall/sonicos<= 7.0.1-r579

How to fix CVE-2021-20031

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-20031 is not in CISA KEV. FIRST estimates a 12.98% chance of exploitation in the next 30 days. Check whether you run A Host Header Redirection.

Which versions are affected?

Compare what you have installed with <= 6.0.5.3-94o, <= 6.5.1.12, <= 6.5.4.7, <= 7.0.1-r1262, <= 7.0.1-r1283, <= 7.0.1-r579. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-601: URL Redirection to Untrusted Site (Open Redirect). EPSS 12.98%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

SonicWall SonicOS security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 12, 2021 · Monitored products — critical

    Detected

    A Host Header Redirection vulnerability in SonicOS potentially allows a remote attacker to redirect firewall management users to arbitrary web domains.

  2. Jun 17, 2026 · Monitored products — critical

    Updated

    A Host Header Redirection vulnerability in SonicOS potentially allows a remote attacker to redirect firewall management users to arbitrary web domains.

Sources

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • Packet Storm SecurityNov 8, 2026
  • FIRST EPSSNov 7, 2026
  • CVE.orgNov 4, 2026
  • Monitored products — criticalNov 2, 2026