Ips Sensor SoftwareApplication · Cisco
CVE-2006-4911
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 · uneditedUnspecified vulnerability in Cisco IPS 5.0 before 5.0(6p2) and 5.1 before 5.1(2), when running in inline or promiscuous mode, allows remote attackers to bypass traffic inspection via a "crafted sequence of fragmented IP packets".
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 confidenceCisco Intrusion Prevention System (IPS) versions 5.0 before 5.0(6p2) and 5.1 before 5.1(2) contain an unspecified vulnerability when operating in inline or promiscuous mode. Remote attackers can bypass traffic inspection by sending a crafted sequence of fragmented IP packets, allowing malicious traffic to pass through the IPS undetected.
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
Ips Sensor SoftwareApplication
>= 5.0, < 5.0\(6p2\)>= 5.1, < 5.1\(2\)CVSS 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
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:L/Au:N/C:P/I:P/A:P
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.
-
Determine Cisco IPS software versionLog into the IPS CLI and run the 'show version' or 'show module' command to display the installed software version.Affected if The version shown is 5.0.x where x is less than 6p2, or 5.1.x where x is less than 2.
-
Verify IPS is running in inline or promiscuous modeExecute the 'show interface' or 'show running-config' command in the IPS CLI to check the interface configuration and operational mode.Affected if The output indicates the sensor is configured in inline mode or promiscuous mode (also called VLAN pair or inline VLAN pair mode).
-
Confirm traffic inspection is activeRun the 'show statistics ips' or 'show service ips' command to verify that packet inspection is enabled and the sensor is actively analyzing traffic.Affected if The sensor shows active traffic inspection and the version falls within the affected range (5.0 < 5.0(6p2) or 5.1 < 5.1(2)).
A Cisco IPS sensor is affected if it runs software version 5.0 before 5.0(6p2) or 5.1 before 5.1(2) AND is operating in inline or promiscuous mode with active traffic inspection.
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 data5.05.1
Upgrade Cisco IPS software to version 5.0(6p2) or later for the 5.0 branch, or 5.1(2) or later for the 5.1 branch. If immediate patching is not feasible, implement additional network-layer filtering to inspect and reassemble fragmented packets before reaching the IPS.
Fix this in Ips Sensor Software
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 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 $3,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2006-4911 — 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-2006-4911 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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
- No spam, self-promotion, credentials, or personal data