dbcve.org
Ios XeOperating system · Cisco

CVE-2021-1622

HIGH · 8.6 CVSS v3.1 Published 2021-09-23
Fix available
A fix is available. Upgrade to 16.12.1z1 or later.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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
A vulnerability in the Common Open Policy Service (COPS) of Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, remote attacker to cause resource exhaustion, resulting in a denial of service (DoS) condition. This vulnerability is due to a deadlock condition in the code when processing COPS packets under certain conditions. An attacker could exploit this vulnerability by sending COPS packets with high burst rates to an affected device. A successful exploit could allow the attacker to cause the CPU to consume excessive resources, which prevents other control plane processes from obtaining resources and results in a DoS.

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

A detailed technical summary for this CVE is being prepared.

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 XeOperating system
Affected:< 16.12.1z1= 17.3.1x

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
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

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.

dbcve · scoped
Upgrade available Upgrade to 16.12.1z1 or later
Fixed in 16.12.1z1
Vendor patch tools.cisco.com →
Recommended fix High confidence

IOS XE 16.12.1z1 or later (for 16.x branches); any 17.x release after 17.3.1x for 17.x branches

  1. 1. Identify the current Cisco IOS XE version on the cBR-8 device using 'show version' command
  2. 2. Confirm the running version is either below 16.12.1z1 or exactly 17.3.1x to determine if affected
  3. 3. Review Cisco Security Advisory cisco-sa-cbr8-cops-Vc2ZsJSx at tools.cisco.com for complete fixed version list
  4. 4. Schedule a maintenance window appropriate for a control plane software upgrade
  5. 5. Backup the current device configuration using 'copy running-config startup-config' or archive export
  6. 6. Upgrade Cisco IOS XE to version 16.12.1z1 or later (or a fixed 17.x release beyond 17.3.1x) using standard Cisco software installation procedures
  7. 7. After reboot, verify the new IOS XE version is installed using 'show version'
  8. 8. Confirm COPS protocol functionality and overall device stability
Caveat Standard IOS XE upgrade considerations apply - verify hardware platform support for target version, review release notes for any behavioral changes, and plan for possible configuration adjustments

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,950. Get the upgrade done

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-1622 — 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-2021-1622 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