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TI-2026-16255 Aliases CVE-2026-20040GHSA-4x82-6phf-h73c

Cisco IOS XR Software CLI Privilege Escalation Vulnerability

Priority LOW 39CWE-78Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-78.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00195 9th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
CiscoCisco IOS XR Software6.5.3; 6.5.29; 6.5.1; 6.6.1; 6.5.2; 6.5.92; 6.5.15; 6.6.2; 7.0.1; 6.6.25; 6.5.26; 6.6.11; 6.5.25; 6.5.28; 6.5.93; 6.6.12; 6.5.90; 7.1.1; 7.0.90; 6.6.3; 6.7.1; 7.0.2; 7.1.15; 7.2.1; 7.1.2; 6.7.2; 7.0.11; 7.0.12; 7.0.14; 7.1.25; 6.6.4; 7.2.12; 7.3.1; 7.1.3; 6.7.3; 7.4.1; 7.2.2; 6.7.4; 6.5.31; 7.3.15; 7.3.16; 6.8.1; 7.4.15; 6.5.32; 7.3.2; 7.5.1; 7.4.16; 7.3.27; 7.6.1; 7.5.2; 7.8.1; 7.6.15; 7.5.12; 7.8.12; 7.3.3; 7.7.1; 6.8.2; 7.3.4; 7.4.2; 6.7.35; 6.9.1; 7.6.2; 7.5.3; 7.7.2; 6.9.2; 7.9.1; 7.10.1; 7.8.2; 7.5.4; 6.5.33; 7.8.22; 7.7.21; 7.9.2; 7.3.5; 7.5.5; 7.11.1; 7.9.21; 7.10.2; 24.1.1; 7.6.3; 7.3.6; 7.5.52; 7.11.2; 24.2.1; 24.1.2; 24.2.11; 24.3.1; 24.4.1; 24.2.2; 7.8.23; 7.11.21; 24.2.20; 24.3.2; 24.4.10; 6.5.35; 25.1.1; 24.4.2; 24.3.20; 24.4.15; 25.2.1; 6.5.351; 25.1.2; 24.3.30; 25.3.1; 6.5.352; 24.4.30; 24.2.21; 25.4.1; 25.2.2; 25.2.15; 7.2.0; 7.0.0; 25.2.30; 6.5.353; 25.1.30; 25.3.15—No fix listedCNA
  • Cisco IOS XR Software VendorCisco Affected 6.5.3; 6.5.29; 6.5.1; 6.6.1; 6.5.2; 6.5.92; 6.5.15; 6.6.2; 7.0.1; 6.6.25; 6.5.26; 6.6.11; 6.5.25; 6.5.28; 6.5.93; 6.6.12; 6.5.90; 7.1.1; 7.0.90; 6.6.3; 6.7.1; 7.0.2; 7.1.15; 7.2.1; 7.1.2; 6.7.2; 7.0.11; 7.0.12; 7.0.14; 7.1.25; 6.6.4; 7.2.12; 7.3.1; 7.1.3; 6.7.3; 7.4.1; 7.2.2; 6.7.4; 6.5.31; 7.3.15; 7.3.16; 6.8.1; 7.4.15; 6.5.32; 7.3.2; 7.5.1; 7.4.16; 7.3.27; 7.6.1; 7.5.2; 7.8.1; 7.6.15; 7.5.12; 7.8.12; 7.3.3; 7.7.1; 6.8.2; 7.3.4; 7.4.2; 6.7.35; 6.9.1; 7.6.2; 7.5.3; 7.7.2; 6.9.2; 7.9.1; 7.10.1; 7.8.2; 7.5.4; 6.5.33; 7.8.22; 7.7.21; 7.9.2; 7.3.5; 7.5.5; 7.11.1; 7.9.21; 7.10.2; 24.1.1; 7.6.3; 7.3.6; 7.5.52; 7.11.2; 24.2.1; 24.1.2; 24.2.11; 24.3.1; 24.4.1; 24.2.2; 7.8.23; 7.11.21; 24.2.20; 24.3.2; 24.4.10; 6.5.35; 25.1.1; 24.4.2; 24.3.20; 24.4.15; 25.2.1; 6.5.351; 25.1.2; 24.3.30; 25.3.1; 6.5.352; 24.4.30; 24.2.21; 25.4.1; 25.2.2; 25.2.15; 7.2.0; 7.0.0; 25.2.30; 6.5.353; 25.1.30; 25.3.15 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:*before 25.2.21; 25.3.1 to before 25.4.2VulnerableCisco
  • cpe:2.3:o:cisco:ios_xr:*:*:*:*:*:*:*:* Versions before 25.2.21; 25.3.1 to before 25.4.2 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-20040
  2. 2026-10-03 Alias added: GHSA-4x82-6phf-h73c

References

Advisory 1

  • TI-2020-02680 Cisco IOS XR Software Cisco Discovery Protocol Format String Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2018-00135 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.8
  • TI-2020-03113 Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerabilities KEVCVSS 3.1HIGH 8.6
  • TI-2020-03110 Cisco IOS XR Software DVMRP Memory Exhaustion Vulnerability KEVCVSS 3.1HIGH 8.6
  • TI-2018-00142 Memory corruption in Cisco IOS, IOS XE, and IOS XR KEVCVSS 3.1HIGH 8.0
  • TI-2023-23979 The HTTP/2 protocol allows a denial of service (server resource consumption) because… KEVCVSS 3.1HIGH 7.5
See all 199 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences