CVE-2019-5273
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 · uneditedUSG9500 with versions of V500R001C30;V500R001C60 have a denial of service vulnerability. Due to a flaw in the X.509 implementation in the affected products which can result in a large heap buffer overrun error, an attacker may exploit the vulnerability by a malicious certificate, resulting a denial of service on the affected products.
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 confidenceThe USG9500 firewall has a heap buffer overflow vulnerability in its X.509 certificate parsing implementation. An attacker can exploit this by presenting a specially crafted malicious certificate, causing a denial of service condition on the affected device.
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= v500r001c30= v500r001c60CVSS 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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Determine USG9500 firmware versionAccess the device CLI and run the command 'display version' or 'display device version' to view the installed firmware versionAffected if The displayed version is exactly v500r001c30 or v500r001c60
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Identify if SSL/TLS inspection is enabledCheck the security policy configuration using 'display security-policy rule all' or 'display ssl inspection' to see if SSL deep inspection is configuredAffected if SSL/TLS inspection is enabled and the device is parsing X.509 certificates from external connections
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Verify if certificate-based VPN is configuredCheck VPN configuration with 'display ipsec sa' or 'display ike sa' to see if IPsec or SSL VPN with certificate authentication is activeAffected if Certificate-based VPN authentication is configured and the device processes peer certificates
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Confirm if external certificate validation is occurringReview logs and certificate handling modules using 'display logbuffer' or check the device's certificate store with 'display certificate'Affected if The device is accepting and parsing X.509 certificates from untrusted or external sources
You are affected if your USG9500 runs firmware version v500r001c30 or v500r001c60 AND the device is configured to parse or validate X.509 certificates from external sources (SSL inspection, certificate-based VPN, or TLS authentication).
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 dataApply vendor-supplied patches for versions V500R001C30 and V500R001C60. If patching is delayed, consider restricting or validating certificates presented to the device until the patch can be deployed.
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2019-5273 — 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-2019-5273 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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