Security readout for executives and security teams
Plain-English summary
This CVE describes an information leak in Comcast firmware on Cisco DPC3939 gateways. A nearby or otherwise able remote user connected through the device's xfinitywifi hotspot could learn the cable modem MAC address. The source bundle does not show device takeover, data theft, or service disruption.
Executive priority
Handle through asset hygiene and vendor follow-up rather than emergency response. Business urgency is low unless the organization depends on these gateways at scale or uses cable modem MAC addresses in sensitive support, provisioning, or tracking processes.
Technical view
The reported issue affects Cisco DPC3939 Comcast firmware builds dpc3939-P20-18-v303r20421733-160420a-CMCST and dpc3939-P20-18-v303r20421746-170221a-CMCST. The weakness exposes the CM MAC address to a remote attacker connected to the xfinitywifi hotspot. No CVSS, CWE, CPE, or patch detail is provided in the supplied sources.
Likely exposure
Exposure appears limited to Comcast-firmware Cisco DPC3939 devices on the two named firmware versions, especially where the xfinitywifi hotspot is enabled and reachable. The provided CVE metadata lists no normalized affected vendor, product, or CPE data.
Exploitation context
The source bundle reports remote discovery of the CM MAC address via hotspot access. CISA KEV status is false, and the supplied sources do not state active exploitation in the wild. Treat this as an information disclosure issue, not proven device compromise.
Researcher notes
The public record is sparse. It identifies two firmware strings and the leaked value, but does not provide CVSS, CWE, affected CPEs, remediation detail, or confirmed exploit activity. Analysis should avoid broadening scope beyond Comcast-firmware Cisco DPC3939 devices named in the CVE.
Mitigation direction
- Identify Cisco DPC3939 gateways and compare firmware with the two named builds.
- Check Comcast or device-management guidance for updated firmware or service-side remediation.
- Disable or restrict the xfinitywifi hotspot where operationally allowed.
- Avoid treating the CM MAC address as a secret authentication factor.
Validation and detection
- Inventory deployed DPC3939 devices and record Comcast firmware versions.
- Confirm whether xfinitywifi hotspot service is enabled on affected devices.
- Review vendor or ISP support channels for remediation status.
- Track whether exposed CM MACs are used in internal asset or support workflows.
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.
CVE-2017-9477 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/BastilleResearch/CableTap/blob/master/doc/advisories/bastille-19.wifi-dhcp-cm-mac-leak.txtCVE reference · x_refsource_MISC
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.