dbcve.org
Ios XrOperating system · Cisco

CVE-2016-1361

MEDIUM · 5.3 CVSS v3.0 Published 2016-03-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
No privileges Zero-click

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 · unedited
Cisco IOS XR through 4.3.2 on Gigabit Switch Router (GSR) 12000 devices does not properly check for a Bidirectional Forwarding Detection (BFD) header in a UDP packet, which allows remote attackers to cause a denial of service (line-card restart) via a crafted packet, aka Bug ID CSCuw56900.

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 confidence

Cisco IOS XR through version 4.3.2 on GSR 12000 devices lacks proper validation of Bidirectional Forwarding Detection (BFD) headers in incoming UDP packets. When a crafted UDP packet without a valid BFD header is received, it triggers a line-card restart, causing denial of service.

MitigationApply the Cisco IOS XR security patch for CSCuw56900 or upgrade to a patched version. Until patched, consider filtering UDP packets destined to BFD ports at network boundaries.

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
Affected:= 3.3.3= 3.4.1= 3.4.2= 3.4.3= 3.5.2= 3.5.3= 3.5.4= 3.6.0= 3.6.1= 3.6.2= 3.6.3= 3.7.0

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
Adjacent
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.0/AV:A/AC:H/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the device model
    Run 'show version' or 'show platform' to confirm the hardware is a Cisco GSR 12000 Series Router or a router running Cisco IOS XR software
    Affected if Device is not a Cisco IOS XR platform on GSR 12000 hardware - the vulnerability does not apply
  2. Check the Cisco IOS XR version
    Run 'show version' and look for the IOS XR release number in the output (e.g., 3.3.3, 3.4.1, 3.5.4, etc.)
    Affected if Version matches 3.3.3, 3.4.1, 3.4.2, 3.4.3, 3.5.2, 3.5.3, 3.5.4, 3.6.0, 3.6.1, 3.6.2, 3.6.3, or 3.7.0 - these are the vulnerable versions
  3. Verify if BFD is enabled
    Run 'show bfd session' or 'show bfd summary' to check if any BFD sessions are configured and active
    Affected if BFD is actively configured and running - the flaw only triggers when BFD processes a crafted UDP packet; if BFD is not enabled, the device is not vulnerable to this specific attack vector

The device is affected if it is a GSR 12000 running Cisco IOS XR version 3.3.3 through 3.7.0 and has BFD functionality enabled or configured.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco IOS XR security patch for CSCuw56900 or upgrade to a patched version. Until patched, consider filtering UDP packets destined to BFD ports at network boundaries.

Fix this in Ios Xr Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,832.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2016-1361 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-1361 in production — separate from our analysis above.

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.

What this is

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.

What belongs here
  • 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