CVE-2019-12647

Cisco IOS and IOS XE Software IP Ident Denial of Service Vulnerability

HIGH

7.5

CVSS Score

Published: September 25, 2019 at 08:05 PM UTC

Updated: June 17, 2026 at 02:15 AM UTC

29 products affected across 1 vendorIOS XeAsr 1002-xAsr 1001-X

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Severity

HIGH7.5

Exploit prediction

EPSS 2%

SSVC

No known exploit

Description

A vulnerability in the Ident protocol handler of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability exists because the affected software incorrectly handles memory structures, leading to a NULL pointer dereference. An attacker could exploit this vulnerability by opening a TCP connection to specific ports and sending traffic over that connection. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

IOS Xe · Cisco

95%

fuji-16.7.1 fuji-16.8.1

cisco-1100 (environment) · cisco-4221 (environment) · cisco-4321 (environment) · cisco-4351 (environment) · cisco-4431 (environment) · cisco-4451-x (environment) · cisco-asr-1000 (environment) · cisco-asr-1001-hx (environment) · cisco-asr-1001-x (environment) · cisco-asr-1002-hx (environment) · cisco-asr-1002-x (environment) · cisco-asr-900 (environment) · cisco-asr-920-10sz-pd (environment) · cisco-asr-920-12cz-a (environment) · cisco-asr-920-12cz-d (environment) · cisco-asr-920-12sz-im (environment) · cisco-asr-920-24sz-im (environment) · cisco-asr-920-24sz-m (environment) · cisco-asr-920-24tz-m (environment) · cisco-asr-920-4sz-a (environment) · cisco-asr-920-4sz-d (environment) · cisco-cloud-services-router-1000v (environment) · cisco-ncs-4201 (environment) · cisco-ncs-4202 (environment) · cisco-ncs-4206 (environment) · cisco-ncs-4216 (environment) · cisco-network-convergence-system-520 (environment)

IOS · Cisconpm

60%

v < 12.1(12)

Affected range stops below 12.1(12), so it looks safe — our inference, not a vendor statement

1100 · Ciscodevice

80%

All versions

4221 · Ciscodevice

80%

All versions

4321 · Ciscodevice

80%