CVE-2026-20040
CVE-2026-20040 is a high-severity vulnerability in Cisco Ios Xr with a CVSS 3.x base score of 8.8. 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 8.8)
- EPSS exploit prediction: 0% (7th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-11214
- Weakness: CWE-78
- Affected product: Cisco Ios Xr
- Published:
- Last modified:
Description
A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of user arguments that are passed to specific CLI commands. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root and execute arbitrary commands on the underlying operating system.
Frequently asked questions
- What is CVE-2026-20040?
- A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of user arguments that are passed to specific CLI commands. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root and execute arbitrary commands on the underlying operating system.
- How severe is CVE-2026-20040?
- CVE-2026-20040 has a CVSS 3.x base score of 8.8, 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-2026-20040 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-20040?
- CVE-2026-20040 affects Cisco Ios Xr. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-20040?
- 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.
- Does CVE-2026-20040 have an EU (EUVD) identifier?
- Yes. CVE-2026-20040 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-11214.
- When was CVE-2026-20040 published?
- CVE-2026-20040 was published on 2026-03-11 and last updated on 2026-07-01.
References
Affected products (1)
- cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*
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