How severe is CVE-2021-34728?

CVE-2021-34728 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-34728 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-2021-34728?

CVE-2021-34728 affects Cisco Ios Xr. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-34728?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-34728 published?

CVE-2021-34728 was published on 2021-09-09 and last updated on 2026-06-17.

CVE-2021-34728

CVE-2021-34728 is a high-severity vulnerability in Cisco Ios Xr with a CVSS 3.x base score of 7.8. 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: High (CVSS 3.x base score 7.8)
CVSS v2: 7.2
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 with a low-privileged account to elevate privileges on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Frequently asked questions

What is CVE-2021-34728?: Multiple vulnerabilities in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker with a low-privileged account to elevate privileges on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.
How severe is CVE-2021-34728?: CVE-2021-34728 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-34728 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-2021-34728?: CVE-2021-34728 affects Cisco Ios Xr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-34728?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-34728 published?: CVE-2021-34728 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-privescal-dZYMrKf

Affected products (1)

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

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