CVE-2021-1376

CVE-2021-1376 is a medium-severity vulnerability in Cisco Ios Xe 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-347.

Key facts

Description

Multiple vulnerabilities in the fast reload feature of Cisco IOS XE Software running on Cisco Catalyst 3850, Cisco Catalyst 9300, and Cisco Catalyst 9300L Series Switches could allow an authenticated, local attacker to either execute arbitrary code on the underlying operating system, install and boot a malicious software image, or execute unsigned binaries on an affected device. These vulnerabilities are due to improper checks performed by system boot routines. To exploit these vulnerabilities, the attacker would need privileged access to the CLI of the device. A successful exploit could allow the attacker to either execute arbitrary code on the underlying operating system or execute unsigned code and bypass the image verification check part of the secure boot process. For more information about these vulnerabilities, see the Details section of this advisory.

Frequently asked questions

What is CVE-2021-1376?
Multiple vulnerabilities in the fast reload feature of Cisco IOS XE Software running on Cisco Catalyst 3850, Cisco Catalyst 9300, and Cisco Catalyst 9300L Series Switches could allow an authenticated, local attacker to either execute arbitrary code on the underlying operating system, install and boot a malicious software image, or execute unsigned binaries on an affected device. These vulnerabilities are due to improper checks performed by system boot routines. To exploit these vulnerabilities, the attacker would need privileged access to the CLI of the device. A successful exploit could allow the attacker to either execute arbitrary code on the underlying operating system or execute unsigned code and bypass the image verification check part of the secure boot process. For more information about these vulnerabilities, see the Details section of this advisory.
How severe is CVE-2021-1376?
CVE-2021-1376 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-2021-1376 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-1376?
CVE-2021-1376 primarily affects Cisco Ios Xe. In total, 50 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-1376?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-1376 published?
CVE-2021-1376 was published on 2021-03-24 and last updated on 2026-06-17.

References

Affected products (50)

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