Web Security ApplianceApplication · Cisco
CVE-2021-1490
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 web-based management interface of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a user of the interface of an affected device. This vulnerability is due to improper validation of user-supplied input in the web-based management interface. An attacker could exploit this vulnerability by persuading a user to retrieve a crafted file that contains malicious payload and upload it to the affected device. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.
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 confidenceCross-site scripting (XSS) vulnerability in Cisco Web Security Appliance web-based management interface due to improper validation of user-supplied input. Attackers can exploit by tricking users into uploading crafted files containing malicious JavaScript payloads, enabling execution in the context of the affected interface.
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
Web Security ApplianceApplication
< 14.0CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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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Confirm the device is a Cisco Web Security ApplianceCheck the system hostname, model identifier, or running processes for 'Cisco WSA' or 'Web Security Appliance' references. Access the CLI and run 'show version' or check the web management login page for Cisco WSA branding.Affected if The device is confirmed to be a Cisco Web Security Appliance
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Determine the installed WSA versionRun the CLI command 'version' or 'show version', or log into the web management interface and navigate to System Administration > Management Interface to view the version number.Affected if The installed version is any release prior to 14.0 (for example, 13.x, 12.x, etc.)
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Verify the web-based management interface is enabledCheck via CLI with 'show interface' or 'show http', or confirm you can access the WSA web management login page over HTTPS (port 8443 or 443).Affected if The web-based management interface is accessible and running
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Confirm file upload functionality exists in the management interfaceLog into the WSA web management and look for file upload features, typically under System Administration, Reporting, or Policy configuration sections. Alternatively, check documentation for your specific version for file upload capabilities.Affected if File upload functionality is present and accessible to users in the management interface
You are affected if your device is a Cisco Web Security Appliance running version prior to 14.0 with the web management interface enabled and file upload capability accessible.
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 data14.0
Apply Cisco-provided patches for WSA when available; implement proper input validation and output encoding for file upload functionality in the web management interface.
Fix this in Web Security Appliance
Scoped from the published advisory
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,960.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-1490 — 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-2021-1490 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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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.
- 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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