How severe is CVE-2021-1370?

CVE-2021-1370 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-2021-1370 being actively exploited?

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

What products are affected by CVE-2021-1370?

CVE-2021-1370 affects Cisco Ios Xr. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-1370?

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-2021-1370 published?

CVE-2021-1370 was published on 2021-02-04 and last updated on 2026-06-17.

CVE-2021-1370

CVE-2021-1370 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% (30th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Cisco Ios Xr
Published: 2021-02-04
Last modified: 2026-06-17

Description

A vulnerability in a CLI command of Cisco IOS XR Software for the Cisco 8000 Series Routers and Network Convergence System 540 Series Routers running NCS540L software images could allow an authenticated, local attacker to elevate their privilege to root. To exploit this vulnerability, an attacker would need to have a valid account on an affected device. The vulnerability is due to insufficient validation of command line arguments. An attacker could exploit this vulnerability by authenticating to the device and entering a crafted command at the prompt. A successful exploit could allow an attacker with low-level privileges to escalate their privilege level to root.

Frequently asked questions

What is CVE-2021-1370?: A vulnerability in a CLI command of Cisco IOS XR Software for the Cisco 8000 Series Routers and Network Convergence System 540 Series Routers running NCS540L software images could allow an authenticated, local attacker to elevate their privilege to root. To exploit this vulnerability, an attacker would need to have a valid account on an affected device. The vulnerability is due to insufficient validation of command line arguments. An attacker could exploit this vulnerability by authenticating to the device and entering a crafted command at the prompt. A successful exploit could allow an attacker with low-level privileges to escalate their privilege level to root.
How severe is CVE-2021-1370?: CVE-2021-1370 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-2021-1370 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1370?: CVE-2021-1370 affects Cisco Ios Xr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-1370?: 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-2021-1370 published?: CVE-2021-1370 was published on 2021-02-04 and last updated on 2026-06-17.

References

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxr-pe-QpzCAePe

Affected products (1)

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

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