CVE-2021-20031Public exploitNetwork attack vector

Open redirect via trusted Host header

Published Oct 12, 2021 · Updated Aug 3, 2024

Host header injection in SonicWall SonicOS allows remote attackers to redirect firewall management users to arbitrary web domains. The unauthenticated HTTP management handler trusts the request Host header and embeds it into the JavaScript jumpURL and login-page link without validation. A management user must process the poisoned response; the browser then leaves the firewall for the attacker-chosen domain, with no reported direct effect on firewall availability.

CVSS severity6.1
Medium
EPSS probability13.04%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Host header injection in SonicWall SonicOS allows remote attackers to redirect firewall management users to arbitrary web domains. The unauthenticated HTTP management handler trusts the request Host header and embeds it into the JavaScript jumpURL and login-page link without validation. A management user must process the poisoned response; the browser then leaves the firewall for the attacker-chosen domain, with no reported direct effect on firewall availability.

The record

CVE
CVE-2021-20031
Published
Oct 12, 2021
Updated
Aug 3, 2024
Vendor
SonicWall
Product
SonicOS
Classifications
CWE-601, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.9.1.13 and earlier
  2. Affected versionversion=6.0.5.3-94o and earlier
  3. Affected versionversion=6.5.1.12 and earlier
  4. Affected versionversion=6.5.4.4-44V-21-987 and earlier
  5. Affected versionversion=6.5.4.7 and earlier
  6. Affected versionversion=7.0.1-R1262 and earlier
  7. Affected versionversion=7.0.1-R1283 and earlier
  8. Affected versionversion=7.0.1-R579 and earlier

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SonicWall · SonicOSversion=5.9.1.13 and earlier; version=6.0.5.3-94o and earlier; version=6.5.1.12 and earlier; version=6.5.4.4-44V-21-987 and earlier; version=6.5.4.7 and earlier; version=7.0.1-R1262 and earlier; version=7.0.1-R1283 and earlier; version=7.0.1-R579 and earlier

Published CVSS scores

5.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-601URL Redirection to Untrusted Site ('Open Redirect')
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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