Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker force an affected Cisco IOS XE device to reload, causing a denial of service. The business risk is service interruption on network infrastructure where RESTCONF or NETCONF-YANG is reachable and uses the affected ACL handling.
Executive priority
Treat as high priority for exposed network infrastructure because exploitation can interrupt routing or switching availability. Urgency depends on whether RESTCONF or NETCONF-YANG is enabled and reachable.
Technical view
CVE-2020-3407 is a Cisco IOS XE RESTCONF and NETCONF-YANG ACL processing flaw. Incorrect ACL handling tied to those features can trigger a device reload. CVSS 3.0 is 8.6, network exploitable, low complexity, no privileges or user interaction, with high availability impact only.
Likely exposure
Exposure is most likely on Cisco IOS XE devices with RESTCONF or NETCONF-YANG enabled and reachable. The source bundle does not identify specific affected versions beyond Cisco IOS XE Software.
Exploitation context
The source bundle describes unauthenticated remote exploitation through RESTCONF or NETCONF-YANG access. It does not cite active exploitation, and KEV status is false.
Researcher notes
Evidence is limited to the CVE record and Cisco advisory reference. The bundle does not include affected release ranges, fixed versions, workarounds, proof-of-concept status, or exploitation observations.
Mitigation direction
- Review Cisco advisory cisco-sa-confacl-HbPtfSuO for fixed software and supported workarounds.
- Inventory Cisco IOS XE devices with RESTCONF or NETCONF-YANG enabled.
- Prioritize devices where management interfaces are reachable from untrusted networks.
- Apply vendor-recommended updates or configuration changes when identified.
- Monitor for unexpected IOS XE reloads affecting availability.
Validation and detection
- Confirm whether each Cisco IOS XE device has RESTCONF or NETCONF-YANG enabled.
- Check whether ACLs are configured for those management features.
- Compare device software against Cisco advisory affected and fixed release guidance.
- Review device logs for unexpected reloads or availability interruptions.
- Document internet or untrusted-network reachability for management interfaces.
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-476: Exact CWE lookup
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Open ATT&CK lookupCVE-2020-3407 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
- 20200924 Cisco IOS XE Software RESTCONF and NETCONF-YANG Access Control List 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.