Web Security ApplianceHardware / appliance · Cisco
CVE-2013-5537
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 · uneditedThe web framework on Cisco Web Security Appliance (WSA), Email Security Appliance (ESA), and Content Security Management Appliance (SMA) devices does not properly manage the state of HTTP and HTTPS sessions, which allows remote attackers to cause a denial of service (management GUI outage) via multiple TCP connections, aka Bug IDs CSCuj59411, CSCuf89818, and CSCuh05635.
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 web framework of Cisco WSA, ESA, and SMA appliances allows remote attackers to cause denial of service via multiple TCP connections due to improper HTTP/HTTPS session state management, leading to management GUI outage.
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 ApplianceHardware / appliance
all versions
Content Security Management ApplianceHardware / appliance
all versions
Email Security Appliance FirmwareOperating system
all versionsCVSS 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
- Authentication
- None
- Confidentiality
- None
- Integrity
- None
- Availability
- Complete
AV:N/AC:L/Au:N/C:N/I:N/A:C
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 appliance typeDetermine if the target system is a Cisco Web Security Appliance (WSA), Cisco Email Security Appliance (ESA), or Cisco Content Security Management Appliance (SMA). Check the device model, firmware banner, or administrative interface for product identification.Affected if The system is any model of Cisco WSA, ESA, or SMA appliance.
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Verify management GUI accessibilityConfirm the web-based management interface is enabled and reachable. This is typically accessible on port 8443 or 443 for HTTPS management access.Affected if The management GUI is exposed and accessible to network attackers.
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Confirm management interface is network-reachableCheck if the management interface has a reachable TCP port (typically 443/8443 for HTTPS). Use network scanning or check appliance network configuration.Affected if The management interface TCP ports are exposed to untrusted networks.
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Check for connection anomaliesMonitor for unusually high numbers of simultaneous TCP connections to the management interface, which is the attack vector for this denial of service.Affected if The appliance is experiencing or has experienced high concurrent connection counts to the management interface.
If the system is a Cisco WSA, ESA, or SMA appliance with an accessible management GUI, it is affected since all versions of these products are vulnerable to session state exhaustion via TCP connection exhaustion.
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 relevant Cisco firmware updates addressing the session state management flaw (Bug IDs CSCuj59411, CSCuf89818, CSCuh05635) and consider implementing connection rate limiting on the management interface as a compensating control.
Fix this in Web Security Appliance
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 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 $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-5537 — 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-2013-5537 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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