How severe is CVE-2021-34721?

CVE-2021-34721 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-34721 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-34721?

CVE-2021-34721 affects Cisco Ios Xr. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34721?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-34721 published?

CVE-2021-34721 was published on 2021-09-09 and last updated on 2026-06-17.

CVE-2021-34721

CVE-2021-34721 is a medium-severity vulnerability in Cisco Ios Xr with a CVSS 3.x base score of 6.7. 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-78.

Key facts

Severity: Medium (CVSS 3.x base score 6.7)
CVSS v2: 6.9
EPSS exploit prediction: 0% (21st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Cisco Ios Xr
Published: 2021-09-09
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-34721?: 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.
How severe is CVE-2021-34721?: CVE-2021-34721 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-34721 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-34721?: CVE-2021-34721 affects Cisco Ios Xr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34721?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-34721 published?: CVE-2021-34721 was published on 2021-09-09 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-cmd-inj-wbZKvPxc

Affected products (1)

cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*

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