CVE-2019-12664

mediumpriority · track · 30EPSS 0.014 · 73 %ileEURUUS
grimoire priorityP3 · Track
Exploitable?
—
no known exploitation
Likely / severe?
1.43% (73rd) EPSS
CVSS 5 · medium
Is it mine?
42 products
Check your exposure
Who says so?
4 sources
cnnvd · enisa_euvd · fstec_bdu · cisco_csaf

EPSS · scored 2026-10-27

A vulnerability in the Dialer interface feature for ISDN connections in Cisco IOS XE Software for Cisco 4000 Series Integrated Services Routers (ISRs) could allow an unauthenticated, adjacent attacker to pass IPv4 traffic through an ISDN channel prior to successful PPP authentication. The vulnerability is due to insufficient validation of the state of the PPP IP Control Protocol (IPCP). An attacker could exploit this vulnerability by making an ISDN call to an affected device and sending traffic through the ISDN channel prior to successful PPP authentication. Alternatively, an unauthenticated, remote attacker could exploit this vulnerability by sending traffic through an affected device that is configured to exit via an ISDN connection for which both the Dialer interface and the Basic Rate Interface (BRI) have been configured, but the Challenge Handshake Authentication Protocol (CHAP) password for PPP does not match the remote end. A successful exploit could allow the attacker to pass IPv4 traffic through an unauthenticated ISDN connection for a few seconds, from initial ISDN call setup until PPP authentication fails.

01

remediations

Vendor fix, mitigation, or workaround guidance, as published by each source.

A vendor fix is available.

02

cvss

Technical severity, 0–10. One row per scoring source.

7.5
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 4.7–7.5

v2.05mediumAV:N/AC:L/Au:N/C:N/I:P/A:Nprimary · NVD / NIST USexploitability 10 · impact 2.9
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 3.6
v3.04.7mediumCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:Nsecondary · ENISA EU
v3.04.7mediumCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:Nsecondary · psirt@cisco.com USexploitability 2.8 · impact 1.4
v3.04.7mediumCVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:Nsecondary · Cisco PSIRT US
v3.14.7mediumAV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:Nsecondary · FSTEC (BDU) RU
v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N/E:Usecondary · CVSS-BT (t0sche)
03

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS
04

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-287USprimaryCWE-200USCWE-200US
05

affected products (42)

Products and version ranges known to be affected.

showing 20 of 42
06

advisories (1)

Vendor and ecosystem advisories describing this.

  • cisco-sa-20190925-isdn-data-leakCisco IOS XE Software ISDN Data Leak Vulnerability2019-09-25csaf · cisco_csafUS

    A vulnerability in the Dialer interface feature for ISDN connections in Cisco IOS XE Software for Cisco 4000 Series Integrated Services Routers (ISRs) could allow an unauthenticated, adjacent attacker to pass IPv4 traffic through an ISDN channel prior to successful PPP authentication. The vulnerability is due to insufficient validation of the state of the PPP IP Control Protocol (IPCP). An attacker could exploit this vulnerability by making an ISDN call to an affected device and sending traffic through the ISDN channel prior to successful PPP authentication. Alternatively, an unauthenticated, remote attacker could exploit this vulnerability by sending traffic through an affected device that is configured to exit via an ISDN connection for which both the Dialer interface and the Basic Rate Interface (BRI) have been configured, but the Challenge Handshake Authentication Protocol (CHAP) password for PPP does not match the remote end. A successful exploit could allow the attacker to pass IPv4 traffic through an unauthenticated ISDN connection for a few seconds, from initial ISDN call setup until PPP authentication fails. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.

07

also known as (4)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

cnnvdenisa_euvdfstec_bducisco_csafNVDCVE.orgMITRE
published 2019-09-25modified 2026-06-17
10

references (7)

External citations — patches, advisories, analysis.

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