How severe is CVE-2021-20031?

CVE-2021-20031 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-20031 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-20031?

CVE-2021-20031 affects Sonicwall Sonicos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-20031?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-20031 published?

CVE-2021-20031 was published on 2021-10-12 and last updated on 2026-06-17.

CVE-2021-20031

CVE-2021-20031 is a medium-severity vulnerability in Sonicwall Sonicos with a CVSS 3.x base score of 6.1. Its EPSS exploit-prediction score of 13% places it in the 96th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-601.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v2: 5.8
EPSS exploit prediction: 13% (96th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-601
Affected product: Sonicwall Sonicos
Published: 2021-10-12
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2021-20031?: A Host Header Redirection vulnerability in SonicOS potentially allows a remote attacker to redirect firewall management users to arbitrary web domains.
How severe is CVE-2021-20031?: CVE-2021-20031 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-20031 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 13% (96th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-20031?: CVE-2021-20031 affects Sonicwall Sonicos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-20031?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-20031 published?: CVE-2021-20031 was published on 2021-10-12 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:sonicwall:sonicos:*:*:*:*:*:*:*:*

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