AsyncosOperating system · Cisco
CVE-2019-1886
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 the HTTPS decryption feature of Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient validation of Secure Sockets Layer (SSL) server certificates. An attacker could exploit this vulnerability by installing a malformed certificate in a web server and sending a request to it through the Cisco WSA. A successful exploit could allow the attacker to cause an unexpected restart of the proxy process on an affected device.
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 confidenceA vulnerability in the HTTPS decryption feature of Cisco Web Security Appliance allows an unauthenticated remote attacker to cause denial of service. The insufficient validation of SSL server certificates enables an attacker to install a malformed certificate on a web server and trigger an unexpected restart of the proxy process when traffic passes through the affected WSA.
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
AsyncosOperating system
>= 10.5, < 10.5.5-005>= 11.5, < 11.5.2-020
Web Security ApplianceApplication
= 10.5.2-072= 10.5.3-025= 11.7.0-fcs-334CVSS 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
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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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Verify HTTPS decryption feature is enabledLog into the WSA admin interface, navigate to Security Services > HTTPS Proxy, or run 'httpsproxy config' in the CLI to confirm HTTPS decryption is turned onAffected if HTTPS decryption is enabled and the WSA is processing SSL traffic with malformed certificates
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Check the installed AsyncOS versionRun 'version' in the WSA CLI or view the version in the admin dashboard under System Administration > Software UpdatesAffected if The version is 10.5.x before 10.5.5-005, or 11.5.x before 11.5.2-020, or exactly 10.5.2-072, 10.5.3-025, or 11.7.0-fcs-334
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Review proxy process crash logsRun 'grep -i "proxy" /var/log/messages | tail -100' or check the GUI under Reporting > System Logs for proxy process restarts or unexpected crashesAffected if Frequent proxy process restarts are observed without other clear causes
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Confirm the WSA handles external HTTPS trafficVerify the WSA is configured as a forward proxy or transparent proxy handling outbound HTTPS traffic from clientsAffected if The WSA is actively intercepting/decrypting HTTPS traffic from users to external web servers
The environment is affected if HTTPS decryption is enabled, the AsyncOS version falls within the vulnerable ranges listed, and the WSA is processing SSL traffic that could include attacker-controlled certificates.
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 data10.5.5-00511.5.2-020
Apply the vendor-supplied patch for CVE-2019-1886 from Cisco. As a temporary workaround, consider disabling HTTPS decryption until the patch can be applied, or implement additional certificate validation controls at the perimeter.
Fix this in Asyncos
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,040.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-1886 — 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-2019-1886 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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- Version or environment caveats, and links to real fixes
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