CVE-2021-1229 json
Cisco NX-OS Software ICMP Version 6 Memory Leak Denial of Service Vulnerability
published 2021-02-24 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-6696
- cvss
- 5.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.4%
- EPSS 1.4% chance of exploitation in 30 days, percentile 73%
- public exploits
- 0
- none known
Summary
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.
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 2 y ago
Exploit prediction
1.43% chance of exploitation in the next 30 days, higher than 73% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L |
| NVD | 3.1 | 5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:N/A:P |
Affected products
- Cisco Cisco NX-OS Software
Classification
- Weakness
-
- CWE-401 Missing Release of Memory after Effective Lifetime
References
Sources
- CVE List CVE-2021-1229
- NVD CVE-2021-1229
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