CVE Vulnerabilities


Missing Release of Memory after Effective Lifetime

Published: Feb 24, 2021 | Modified: Mar 03, 2021
CVSS 3.x
CVSS 2.x

A vulnerability in ICMP Version 6 (ICMPv6) processing in Cisco NX-OS Software could allow an unauthenticated, remote attacker to cause a slow system memory leak, which over time could lead to a denial of service (DoS) condition. This vulnerability is due to improper error handling when an IPv6-configured interface receives a specific type of ICMPv6 packet. An attacker could exploit this vulnerability by sending a sustained rate of crafted ICMPv6 packets to a local IPv6 address on a targeted device. A successful exploit could allow the attacker to cause a system memory leak in the ICMPv6 process on the device. As a result, the ICMPv6 process could run out of system memory and stop processing traffic. The device could then drop all ICMPv6 packets, causing traffic instability on the device. Restoring device functionality would require a device reboot.


The software does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.

Potential Mitigations

  • Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
  • For example, glibc in Linux provides protection against free of invalid pointers.
  • When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
  • To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.