CVE-2020-5140
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 · uneditedA vulnerability in SonicOS allows a remote unauthenticated attacker to cause Denial of Service (DoS) on the firewall SSLVPN service by sending a malicious HTTP request that leads to memory addresses leak. This vulnerability affected SonicOS Gen 5 version 5.9.1.7, 5.9.1.13, Gen 6 version 6.5.4.7, 6.5.1.12, 6.0.5.3, SonicOSv 6.5.4.v and Gen 7 version SonicOS 7.0.0.0.
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 · high confidenceRemote unauthenticated attacker can cause DoS on SonicOS SSLVPN by sending malicious HTTP requests that leak memory addresses. This is a pre-authentication vulnerability affecting Gen 5 (5.9.1.7, 5.9.1.13), Gen 6 (6.5.4.7, 6.5.1.12, 6.0.5.3), SonicOSv 6.5.4.v, and Gen 7 (7.0.0.0).
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<= 5.9.1.13>= 6.0.0.0, <= 6.0.5.3>= 6.5.0.0, <= 6.5.1.11>= 6.5.4.0, <= 6.5.4.7= 7.0.0.0<= 6.5.4.4CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify the SonicOS versionAccess the SonicWall management interface or CLI and run 'show version' or check System > Status to find the installed SonicOS version numberAffected if The version falls within any of these ranges: <= 5.9.1.13, 6.0.0.0-6.0.5.3, 6.5.0.0-6.5.1.11, 6.5.4.0-6.5.4.7, or equals 7.0.0.0 for Sonicos; or <= 6.5.4.4 for Sonicosv
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Verify SSLVPN is enabledCheck the SonicWall VPN settings: navigate to VPN > SSL VPN in the web interface or run 'show ssl-vpn config' via CLI to determine if the SSLVPN feature is activeAffected if SSLVPN is currently enabled and configured on the device
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Check for memory leak indicatorsMonitor system logs and SSLVPN connection logs for unusual patterns, particularly any log entries showing memory address leaks or unexpected HTTP errors from the SSLVPN serviceAffected if Unusual HTTP errors or memory address patterns appear in logs following SSLVPN access attempts
A user is affected if their SonicOS or Sonicosv version falls within the affected ranges AND SSLVPN is enabled, as the vulnerability is pre-authentication and requires no user interaction to trigger.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpdate SonicOS to patched version provided by SonicWall. If immediate patching is not possible, consider restricting SSLVPN access via upstream firewall rules or disabling the service if not required.
- Consultation3.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-5140 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-5140 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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