Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker overload affected Cisco cBR-8 broadband routers by sending bursts of COPS traffic. The business impact is availability: control-plane resources can be exhausted, disrupting router operations. The provided sources do not show active exploitation or specific fixed releases.
Executive priority
Prioritize for broadband or service-provider networks using Cisco cBR-8 routers. The main risk is service disruption, and remediation should focus on exposure reduction and Cisco-approved software guidance.
Technical view
Cisco describes a COPS processing deadlock in Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers. High-burst COPS packets can drive excessive CPU consumption, starving other control-plane processes and causing DoS. CVSS 3.1 is 8.6, with network attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is most likely in service provider or cable broadband environments using Cisco cBR-8 routers running affected IOS XE Software, especially where COPS traffic can reach the device over the network.
Exploitation context
The bundle supports unauthenticated remote DoS via high-burst COPS packets. It does not include exploit-code evidence, observed exploitation, or CISA KEV listing. Treat this as a serious availability risk, not a confirmed actively exploited issue.
Researcher notes
Evidence is limited to CVE and Cisco advisory metadata in the supplied bundle. The affected scope should not be expanded beyond Cisco cBR-8 IOS XE. No patch version, workaround, or active exploitation claim is provided in the bundle.
Mitigation direction
- Review Cisco’s advisory for fixed releases, workarounds, and deployment-specific guidance.
- Inventory Cisco cBR-8 routers and their IOS XE versions.
- Prioritize remediation for devices reachable by untrusted or broad network paths.
- Assess whether COPS reachability can be restricted without disrupting operations.
- Monitor affected routers for abnormal CPU and control-plane resource exhaustion.
Validation and detection
- Confirm whether any Cisco cBR-8 routers are present in the environment.
- Map which networks can reach COPS services on those routers.
- Check device telemetry for high CPU or control-plane starvation symptoms.
- Verify IOS XE status against Cisco’s advisory and approved remediation guidance.
- Document compensating controls if immediate software remediation is not possible.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-833: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-1622 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.6HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20210922 Cisco IOS XE Software for Cisco cBR-8 Converged Broadband Routers Common Open Policy Service Denial of Service VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deadlock
Deadlock represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.