Security readout for executives and security teams
Plain-English summary
This issue can make a Cisco IOS XR router restart its BGP process, disrupting routing availability. It matters most where IOS XR devices participate in BGP EVPN. Exploitation is constrained because the malicious update must come through a configured BGP peer path, and impact depends on a user viewing EVPN operational route status.
Executive priority
Treat as high priority for networks where Cisco IOS XR carries BGP EVPN traffic. The business risk is routing instability or outage, not data theft. Prioritize exposed routers that support critical provider, data center, or customer connectivity.
Technical view
Cisco describes incorrect processing of BGP EVPN update messages containing crafted EVPN attributes. A malformed attribute can lead to an unexpected BGP process restart when EVPN operational routes are displayed. CVSS v3.0 is 7.4 with network attack vector, no privileges, required user interaction, changed scope, and high availability impact.
Likely exposure
Exposure is most likely on Cisco IOS XR deployments using BGP EVPN, such as service provider or data center routing environments. The source bundle does not identify specific vulnerable releases beyond IOS XR Software, so version exposure must be checked against Cisco guidance.
Exploitation context
The bundle does not cite active exploitation or CISA KEV listing. Cisco states exploitation requires a malicious BGP EVPN update from a configured valid BGP peer, or injection into an existing valid TCP connection to a BGP peer.
Researcher notes
Evidence is strongest for availability impact and exploitation preconditions. The source bundle does not provide affected version ranges, fixed release details, public exploit status, or workaround specifics. Avoid assuming broader Cisco product impact without vendor confirmation.
Mitigation direction
- Check Cisco’s advisory for affected and fixed IOS XR releases.
- Upgrade affected IOS XR devices according to Cisco guidance.
- Limit BGP EVPN peering to explicitly trusted peers.
- Review controls protecting BGP sessions from unauthorized injection.
- Monitor for unexpected BGP process restarts on EVPN routers.
Validation and detection
- Inventory Cisco IOS XR devices running BGP EVPN.
- Compare installed IOS XR releases with Cisco’s advisory.
- Review configured BGP peers and EVPN route exchange boundaries.
- Check logs for unexpected BGP process restarts.
- Confirm operational procedures account for EVPN route display risk.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-399: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2019-16018 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
- 7.4 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H2.84Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.4HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20200122 Cisco IOS XR Software EVPN Operational Routes 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.
Resource Management Errors
Resource Management Errors represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.