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SonicosOperating system · Sonicwall

CVE-2025-40600

CRITICAL · 9.8 CVSS v3.1 Published 2025-07-29
Fix available
A fix is available. Upgrade to 7.3.0-7012 or later.
See remediation →
100/100
Remediation priority · Urgent
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
Use of Externally-Controlled Format String vulnerability in the SonicOS SSL VPN interface allows a remote unauthenticated attacker to cause service disruption.

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 format string vulnerability exists in the SonicOS SSL VPN web interface where user-supplied input is passed to a format-sensitive function without proper sanitization. An unauthenticated remote attacker can send specially crafted requests containing format specifiers (e.g., %s, %x, %n) to the VPN login or related pages, causing the application to interpret these as format string instructions rather than literal text, leading to information disclosure from memory or service crash.

MitigationApply the vendor-supplied SonicOS firmware update addressing CVE-2025-40600 immediately. If no patch is available, restrict SSL VPN interface access to trusted IP addresses via firewall rules or disable the SSL VPN web portal temporarily while monitoring for 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, < 7.3.0-7012

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 the device as a Sonicwall appliance
    Confirm the hardware or virtual appliance is a Sonicwall product running SonicOS firmware. This can be done via the device's web interface, console, or SNMP inventory queries.
    Affected if The device is not a Sonicwall SonicOS appliance, then this CVE does not apply.
  2. Determine the installed SonicOS version
    Access the Sonicwall management interface and navigate to System > Status or use the CLI command 'show version' to retrieve the exact firmware version number.
    Affected if The installed version must be compared against the affected range: version >= 7.1.1-7040 and version < 7.3.0-7012.
  3. Verify SSL VPN is enabled
    Check the SonicOS configuration to determine if the SSL VPN feature is currently enabled. This can be found in the web interface under VPN > SSL VPN Settings or via CLI commands such as 'show ssl-vpn config'.
    Affected if SSL VPN is not enabled, the attack surface for this specific vulnerability may be reduced, though the vulnerable code may still be present in the firmware.
  4. Confirm network exposure of SSL VPN interface
    Review firewall rules or network configuration to determine if the SSL VPN interface (typically port 4433 or 443) is accessible from untrusted networks or the internet.
    Affected if The SSL VPN interface is directly exposed to untrusted networks, making exploitation more likely.

The environment is affected if it is a Sonicwall SonicOS device with SSL VPN enabled running a version between 7.1.1-7040 and 7.3.0-7012 (exclusive of the upper bound).

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 7.3.0-7012 or later
Fixed in 7.3.0-7012
Interim mitigation

Apply the vendor-supplied SonicOS firmware update addressing CVE-2025-40600 immediately. If no patch is available, restrict SSL VPN interface access to trusted IP addresses via firewall rules or disable the SSL VPN web portal temporarily while monitoring for exploitation attempts.

Recommended fix High confidence

7.3.0-7012

  1. Download SonicOS version 7.3.0-7012 or later from the SonicWall support portal
  2. Review the release notes for any special upgrade instructions or prerequisites
  3. Back up the current device configuration
  4. Follow the standard SonicWall firmware upgrade procedure for your appliance
  5. Verify the upgrade was successful and the SSL VPN interface is operational
Caveat Review release notes for version-specific migration considerations

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

Fix this in Sonicos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,970
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,152.

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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-2025-40600 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