Improper verification of cryptographic signature in Cisco 8000 Series Routers and Cisco Network Convergence System 5000 Series - CVE-2021-1136
Published: February 4, 2021 / Updated: February 5, 2021
Vulnerability identifier: #VU50379
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-1136
CWE-ID: CWE-347
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to bypass implemented security restrictions.
The vulnerability exists in the signing functions of ISO packaging of Cisco NCS 540 Series Routers, only when running Cisco IOS XR NCS540L software images, and Cisco IOS XR Software for the Cisco 8000 Series Routers. Unsigned script within the ISO image is not verified during system upgrade before it is executed. A local user can execute unsigned code during the boot process on an affected device.
Affected software
Cisco 8000 Series Routers
Cisco Network Convergence System 5000 Series
Cisco Network Convergence System 5000 Series
How to mitigate CVE-2021-1136
Install updates from vendor's website.
Cisco 8000 Series Routers - addressed in versions 7.0.12.23i.BASE, 7.0.13.2i.BASE, 7.2.1.21i.BASE
Cisco Network Convergence System 5000 Series - addressed in versions 7.0.12.23i.BASE, 7.0.13.2i.BASE, 7.2.1.21i.BASE
Cisco Network Convergence System 5000 Series - addressed in versions 7.0.12.23i.BASE, 7.0.13.2i.BASE, 7.2.1.21i.BASE