How severe is CVE-2017-9478?

CVE-2017-9478 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.

Is CVE-2017-9478 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-9478?

CVE-2017-9478 primarily affects Cisco Dpc3939 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-9478?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2017-9478 published?

CVE-2017-9478 was published on 2017-07-31 and last updated on 2026-06-17.

CVE-2017-9478

CVE-2017-9478 is a high-severity vulnerability in Cisco Dpc3939 Firmware with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Cisco Dpc3939 Firmware
Published: 2017-07-31
Last modified: 2026-06-17

Description

The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST) and DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices sets the CM MAC address to a value with a two-byte offset from the MTA/VoIP MAC address, which indirectly allows remote attackers to discover hidden Home Security Wi-Fi networks by leveraging the embedding of the MTA/VoIP MAC address into the DNS hostname.

Frequently asked questions

What is CVE-2017-9478?: The Comcast firmware on Cisco DPC3939 (firmware version dpc3939-P20-18-v303r20421733-160420a-CMCST) and DPC3939 (firmware version dpc3939-P20-18-v303r20421746-170221a-CMCST) devices sets the CM MAC address to a value with a two-byte offset from the MTA/VoIP MAC address, which indirectly allows remote attackers to discover hidden Home Security Wi-Fi networks by leveraging the embedding of the MTA/VoIP MAC address into the DNS hostname.
How severe is CVE-2017-9478?: CVE-2017-9478 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2017-9478 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-9478?: CVE-2017-9478 primarily affects Cisco Dpc3939 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-9478?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-9478 published?: CVE-2017-9478 was published on 2017-07-31 and last updated on 2026-06-17.

References

https://github.com/BastilleResearch/CableTap/blob/master/doc/advisories/bastille-20.emta-reverse-dns.txt

Affected products (2)

cpe:2.3:o:cisco:dpc3939_firmware:dpc3939-p20-18-v303r20421746-170221a-cmcst:*:*:*:*:*:*:*
cpe:2.3:o:cisco:dpc3939_firmware:dpc3939-p20-18-v303r20421733-160420a-cmcst:*:*:*:*:*:*:*

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