dbcve.org
Ios XrOperating system · Cisco

CVE-2015-0776

MEDIUM · 5.0 CVSS v2.0 Published 2015-06-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable 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
telnetd in Cisco IOS XR 5.0.1 on Network Convergence System 6000 devices allows remote attackers to cause a denial of service (device reload) via a malformed TELNET packet, aka Bug ID CSCuq31566.

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

A denial of service vulnerability exists in the telnetd service of Cisco IOS XR 5.0.1 running on Network Convergence System 6000 devices. Remote attackers can trigger a device reload by sending specially crafted malformed TELNET packets to the affected service.

MitigationApply the vendor patch or upgrade Cisco IOS XR to a version beyond 5.0.1 that addresses this vulnerability. As a compensating control, restrict telnet access via ACLs to trusted management networks or disable telnet and use SSH instead.

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:= 5.0.1

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
None
Integrity
None
Availability
Partial

AV:N/AC:L/Au:N/C:N/I:N/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 checks

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

  1. Identify the device platform
    Run 'show platform' or check the hardware model to confirm the device is a Cisco Network Convergence System 6000 (NCS 6000)
    Affected if The device is not an NCS 6000 platform
  2. Check the Cisco IOS XR version
    Run 'show version' and locate the IOS XR release version in the output
    Affected if The version displayed is 5.0.1 specifically
  3. Verify telnetd service is enabled
    Run 'show telnet server' or 'show running-config | include telnet' to check if the telnet server is configured and active
    Affected if Telnet server is enabled and running
  4. Check telnet access bindings
    Run 'show telnet server' or 'show running-config | include vty' to see which interfaces or IP addresses can reach the telnet service
    Affected if Telnet is accessible from non-management or untrusted network segments

A user is affected if the device is an NCS 6000 running Cisco IOS XR version 5.0.1 with telnetd enabled and accessible from the network segment where attackers can send packets.

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 vendor patch or upgrade Cisco IOS XR to a version beyond 5.0.1 that addresses this vulnerability. As a compensating control, restrict telnet access via ACLs to trusted management networks or disable telnet and use SSH instead.

Fix this in Ios Xr Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2015-0776 — 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-2015-0776 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