CVE-2020-3403

CVE-2020-3403 is a high-severity vulnerability in Cisco Ios Xe 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

Description

A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker to inject a command to the underlying operating system that will execute with root privileges upon the next reboot of the device. The authenticated user must have privileged EXEC permissions on the device. The vulnerability is due to insufficient protection of values passed to a script that executes during device startup. An attacker could exploit this vulnerability by writing values to a specific file. A successful exploit could allow the attacker to execute commands with root privileges each time the affected device is restarted.

Frequently asked questions

What is CVE-2020-3403?
A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker to inject a command to the underlying operating system that will execute with root privileges upon the next reboot of the device. The authenticated user must have privileged EXEC permissions on the device. The vulnerability is due to insufficient protection of values passed to a script that executes during device startup. An attacker could exploit this vulnerability by writing values to a specific file. A successful exploit could allow the attacker to execute commands with root privileges each time the affected device is restarted.
How severe is CVE-2020-3403?
CVE-2020-3403 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-2020-3403 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-2020-3403?
CVE-2020-3403 affects Cisco Ios Xe. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-3403?
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-2020-3403 published?
CVE-2020-3403 was published on 2020-09-24 and last updated on 2026-06-17.

References

Affected products (1)

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