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SonicosOperating system · Sonicwall

CVE-2025-40601

HIGH · 7.5 CVSS v3.1 Published 2025-11-20
Fix available
A fix is available. Upgrade to 7.3.1-7013 / 8.0.3-8011 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A Stack-based buffer overflow vulnerability in the SonicOS SSLVPN service allows a remote unauthenticated attacker to cause Denial of Service (DoS), which could cause an impacted firewall to crash.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A stack-based buffer overflow vulnerability exists in the SonicOS SSLVPN service. By sending specially crafted input to the SSLVPN component, a remote unauthenticated attacker can overflow a stack-allocated buffer, causing the firewall to crash and resulting in denial of service.

MitigationApply the vendor-supplied patch/firmware update for CVE-2025-40601. Until patches are available, consider restricting or disabling SSLVPN access from untrusted networks and monitoring for indicators of exploitation attempts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
SonicosOperating system
Affected:>= 7.1.1-7040, < 7.3.1-7013< 8.0.3-8011

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed SonicOS version
    Log into the Sonicwall web GUI and navigate to System > Status to view the firmware version, or use the CLI command 'show version'
    Affected if The displayed version falls within the range >= 7.1.1-7040 and < 7.3.1-7013, or is < 8.0.3-8011
  2. Confirm SSLVPN service is enabled
    In the Sonicwall web GUI, navigate to SSL-VPN > Settings and verify the SSL-VPN service status, or use the CLI command 'show sslvpn'
    Affected if SSL-VPN is currently enabled and running on the device
  3. Verify SSLVPN is accessible from network
    Check the SSL-VPN interface binding in the web GUI under SSL-VPN > Settings to confirm which interfaces have SSLVPN listening (typically WAN interface for external access)
    Affected if SSLVPN is bound to externally accessible interfaces such as the WAN

You are affected if your SonicOS version is 7.1.1-7040 or higher but below 7.3.1-7013 (or below 8.0.3-8011) AND SSLVPN is enabled and accessible.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.3.1-7013 / 8.0.3-8011 or later
Fixed in 7.3.1-70138.0.3-8011
Interim mitigation

Apply the vendor-supplied patch/firmware update for CVE-2025-40601. Until patches are available, consider restricting or disabling SSLVPN access from untrusted networks and monitoring for indicators of exploitation attempts.

Recommended fix High confidence

Upgrade to SonicOS 7.3.1-7013 or higher in the 7.x branch, OR SonicOS 8.0.3-8011 or higher in the 8.x branch

  1. 1. Identify the current SonicOS firmware version on the firewall via the management interface or CLI (show version)
  2. 2. Determine which version branch (7.x or 8.x) is currently running
  3. 3. If running 7.x branch with version < 7.3.1-7013: plan upgrade to 7.3.1-7013 or later
  4. 4. If running 8.x branch with version < 8.0.3-8011: plan upgrade to 8.0.3-8011 or later
  5. 5. Download the appropriate fixed firmware from the SonicWall support portal (mysonicwall.com)
  6. 6. Verify the firmware is compatible with the specific firewall hardware model
  7. 7. Review SonicWall release notes for any configuration changes required for the target version
  8. 8. Apply the firmware upgrade during a maintenance window following standard SonicWall upgrade procedures
Caveat Review release notes for the target version as minor configuration changes between major releases may be required; test in non-production environment before deploying to production

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Sonicos Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-40601 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data