Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker force affected Cisco IOS or IOS XE network devices to reload, causing a denial of service. Business impact is outage risk for routers or switches that carry critical traffic. The provided sources do not identify active exploitation or exact affected versions.
Executive priority
Treat this as high priority for critical network infrastructure because exploitation could create outages. Prioritize devices exposed to untrusted networks first, then complete fleet verification using Cisco guidance because exact affected and fixed versions are not included in the provided bundle.
Technical view
CVE-2019-12647 is a NULL pointer dereference in the Cisco IOS and IOS XE Ident protocol handler. Incorrect memory-structure handling can be triggered by TCP traffic over a connection to specific ports, causing device reload. It is rated CVSS 3.0 8.6 with network attack vector, low complexity, no privileges, and high availability impact.
Likely exposure
Exposure is most likely where Cisco IOS or IOS XE devices run vulnerable software and are reachable from untrusted networks. The bundle does not provide exact vulnerable releases, fixed releases, or affected port details, so teams must verify against Cisco's advisory and their device inventory.
Exploitation context
The source bundle lists KEV status as false and provides no cited evidence of active exploitation. The issue is still operationally serious because it is unauthenticated, remote, low complexity, and can cause device reload rather than data theft or code execution.
Researcher notes
The evidence supports an unauthenticated remote DoS via NULL pointer dereference in Cisco's Ident protocol handler. The bundle does not include affected version ranges, fixed releases, exact ports, workarounds, proof-of-concept status, or exploitation reports. Avoid assuming broader impact beyond reload-based availability loss.
Mitigation direction
- Check Cisco's advisory for affected releases, fixed software, and any named workarounds.
- Inventory Cisco IOS and IOS XE devices and record running software versions.
- Prioritize remediation for internet-facing or business-critical network devices.
- Limit untrusted reachability to affected services where operationally safe.
- Monitor network devices for unexpected reloads and repeated connection attempts.
Validation and detection
- Compare device software versions against Cisco's advisory for CVE-2019-12647.
- Identify Cisco IOS and IOS XE devices reachable from untrusted networks.
- Review logs for unexplained reloads around suspicious TCP connection activity.
- Confirm any compensating access controls do not disrupt required network services.
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-476: 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-2019-12647 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 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/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:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.6HighVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20190925 Cisco IOS and IOS XE Software IP Ident 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.
NULL Pointer Dereference
NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.