CVE-2021-34727

Cisco IOS XE SD-WAN Software Buffer Overflow Vulnerability

CRITICAL

9.8

CVSS Score

Published: September 23, 2021 at 02:26 AM UTC

Updated: June 17, 2026 at 03:56 AM UTC

49 products affected across 1 vendorIOS Xe Sd WANAsr 1002-xAsr 1004

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Severity

CRITICAL9.8

Exploit prediction

EPSS 3%

SSVC

No known exploit

Description

A vulnerability in the vDaemon process in Cisco IOS XE SD-WAN Software could allow an unauthenticated, remote attacker to cause a buffer overflow on an affected device. This vulnerability is due to insufficient bounds checking when an affected device processes traffic. An attacker could exploit this vulnerability by sending crafted traffic to the device. A successful exploit could allow the attacker to cause a buffer overflow and possibly execute arbitrary commands with root-level privileges, or cause the device to reload, which could result in a denial of service condition.

Affected

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

IOS Xe Sd WAN · Cisco

95%

All versions

cisco-1000-integrated-services-router (environment) · cisco-1100-4g-6g-integrated-services-router (environment) · cisco-1100-4p-integrated-services-router (environment) · cisco-1100-8p-integrated-services-router (environment) · cisco-1100-integrated-services-router (environment) · cisco-1101-4p-integrated-services-router (environment) · cisco-1101-integrated-services-router (environment) · cisco-1109-2p-integrated-services-router (environment) · cisco-1109-4p-integrated-services-router (environment) · cisco-1109-integrated-services-router (environment) · cisco-1111x-8p-integrated-services-router (environment) · cisco-1111x-integrated-services-router (environment) · cisco-111x-integrated-services-router (environment) · cisco-1120-integrated-services-router (environment) · cisco-1160-integrated-services-router (environment) · cisco-4000-integrated-services-router (environment) · cisco-422-integrated-services-router (environment) · cisco-4221-integrated-services-router (environment) · cisco-4321-integrated-services-router (environment) · cisco-4331-integrated-services-router (environment) · cisco-4351-integrated-services-router (environment) · cisco-4431-integrated-services-router (environment) · cisco-4451-integrated-services-router (environment) · cisco-4451-x-integrated-services-router (environment) · cisco-4461-integrated-services-router (environment) · cisco-asr-1000 (environment) · cisco-asr-1000-esp100 (environment) · cisco-asr-1000-series (environment) · cisco-asr-1000-series-route-processor-rp2 (environment) · cisco-asr-1000-series-route-processor-rp3 (environment) · cisco-asr-1000-x (environment) · cisco-asr-1001 (environment) · cisco-asr-1001-hx (environment) · cisco-asr-1001-hx-r (environment) · cisco-asr-1001-x (environment) · cisco-asr-1001-x-r (environment) · cisco-asr-1002 (environment) · cisco-asr-1002-hx (environment) · cisco-asr-1002-hx-r (environment) · cisco-asr-1002-x (environment) · cisco-asr-1002-x-r (environment) · cisco-asr-1004 (environment) · cisco-asr-1006 (environment) · cisco-asr-1006-x (environment) · cisco-asr-1009-x (environment) · cisco-asr-1013 (environment) · cisco-asr-1023 (environment) · cisco-csr-1000v (environment)

1000 Integrated Services Router · Ciscodevice

80%

All versions

1100-4G/6G Integrated Services Router · Ciscodevice

80%

All versions

1100-4P Integrated Services Router · Ciscodevice

80%

All versions

1100-8P Integrated Services Router · Ciscodevice

80%

All versions