Ios XrOperating system · Cisco
CVE-2016-1407
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 · uneditedCisco IOS XR through 5.3.2 mishandles Local Packet Transport Services (LPTS) flow-base entries, which allows remote attackers to cause a denial of service (session drop) by making many connection attempts to open TCP ports, aka Bug ID CSCux95576.
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 IOS XR through version 5.2.3 mishandles Local Packet Transport Services (LPTS) flow-base entries. Remote attackers can cause denial of service by making many connection attempts to open TCP ports, exhausting flow-base entries and causing session drops.
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
Ios XrOperating system
= 2.0.0= 3.0.0= 3.0.1= 3.2.0= 3.2.1= 3.2.2= 3.2.3= 3.2.4= 3.2.6= 3.2.50= 3.3.0= 3.3.1CVSS 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:3.0/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.
-
Determine installed Cisco IOS XR versionExecute 'show version' or 'admin show version' in the IOS XR CLI to retrieve the running software versionAffected if The version shown is any of these: 2.0.0, 3.0.0, 3.0.1, 3.2.0, 3.2.1, 3.2.2, 3.2.3, 3.2.4, 3.2.6, 3.2.50, 3.3.0, 3.3.1 (versions 2.0.0 through 3.3.1 are affected)
-
Confirm LPTS feature is in useExecute 'show lpts flow-ownership brief' to display LPTS flow ownership table and confirm LPTS is active on the systemAffected if The command returns output showing active LPTS flow entries, indicating the feature is enabled and processing traffic
-
Check current flow-base entry utilizationExecute 'show lpts statistics' or 'show lpts pfilter brief' to view current flow-base entry counts and usage statisticsAffected if The output shows high flow-base entry counts approaching configured limits, or the statistics indicate near-exhaustion of available entries
-
Verify external-facing TCP listener configurationReview running configuration with 'show running-config' or check access lists and interface configurations for publicly accessible TCP servicesAffected if The system has externally reachable TCP ports or services that could accept connection attempts from untrusted networks
If the Cisco IOS XR version is 2.0.0 through 3.3.1 and LPTS is actively processing traffic with externally accessible TCP services, the environment is vulnerable to flow-base entry exhaustion via remote connection attempts.
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 dataUpgrade Cisco IOS XR to version 5.3.3 or later per Cisco advisory. If immediate upgrade is not feasible, implement network segmentation and rate limiting to reduce exposure to external attack vectors.
Fix this in Ios Xr
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 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 $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-1407 — 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-2016-1407 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