Cisco IOS XR Software Command Injection Vulnerabilities

published 2021-09-09 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-21371

cvss: 6.7; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 20%
public exploits: 0; none known

Multiple vulnerabilities in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to gain access to the underlying root shell of an affected device and execute arbitrary commands with root privileges. For more information about these vulnerabilities, see the Details section of this advisory.

Patch / fix

fixed in 1

cisco ios_xr 7.3.2, 7.4.1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: 2 y ago (2024-11-07)

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 20% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	6.7	CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD	3.1	6.7	CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	6.9	AV:L/AC:M/Au:N/C:C/I:C/A:C

Affected products

Cisco Cisco IOS XR Software

Classification

Weakness

CWE-78 Improper Neutralization of Special Elements used in an OS Command

Technology feeds

Cisco IOS rss critical rss

References

tools.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-cmd-inj-wbZKvPxc
vendor-advisory

Sources

CVE List CVE-2021-34721
NVD CVE-2021-34721

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary