Security readout for executives and security teams
Plain-English summary
CVE-2019-1909 can make affected Cisco IOS XR routers restart their BGP process, disrupting routing. The attacker generally needs access through a valid BGP peer relationship or an existing valid BGP connection, so exposure is narrower than an open internet service but still important for routing infrastructure.
Executive priority
Treat this as a moderate operational resilience issue. It is not broad unauthenticated internet exposure, but a successful attack could disrupt routing on important Cisco IOS XR systems. Prioritize validation and vendor-guided remediation for critical network paths.
Technical view
Cisco describes incorrect processing of certain BGP update messages in IOS XR Software. A crafted update with a specific attribute set can unexpectedly restart the BGP process, causing denial of service. CVSS 3.0 is 6.8 with network attack vector, high attack complexity, changed scope, and high availability impact.
Likely exposure
Organizations using Cisco IOS XR Software with BGP enabled may be exposed. Risk is highest on edge, transit, service-provider, and large enterprise routers with many BGP peers. The source bundle does not identify exact affected IOS XR versions.
Exploitation context
The CVE is not listed as KEV, and the supplied sources do not claim active exploitation. Cisco states exploitation requires a configured valid BGP peer or injection into an existing valid TCP connection to a BGP peer.
Researcher notes
The key constraint is peer trust: Cisco says BGP traffic is accepted only from explicitly defined peers. The bundle does not include affected release ranges, fixed versions, workarounds, or exploitation-in-the-wild evidence, so avoid overclaiming until the Cisco advisory is reviewed.
Mitigation direction
- Review Cisco’s advisory for affected releases and fixed software.
- Inventory Cisco IOS XR devices running BGP.
- Map configured BGP peers and remove unexpected or obsolete peers.
- Prioritize vendor-guided upgrades for critical routing infrastructure.
- Monitor for BGP process restarts, adjacency resets, and route instability.
Validation and detection
- Identify IOS XR routers with BGP enabled.
- Compare running software versions against Cisco’s advisory.
- Review BGP neighbor configuration for trusted, expected peers only.
- Check logs for unexpected BGP process restarts.
- Confirm monitoring alerts cover BGP restarts and routing churn.
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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Open ATT&CK lookupCVE-2019-1909 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:H/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:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H2.24Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
6.8MediumVector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20190703 Cisco IOS XR Software Border Gateway Protocol 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.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.