CVE-2021-20177

Updated: 2025-08-20 00:14:10.683407

Description:

A flaw was found in the Linux kernel's implementation of string matching within a packet. A privileged user (with root or CAP_NET_ADMIN) when inserting iptables rules could insert a rule which can panic the system. Kernel before kernel 5.5-rc1 is affected.


Links NIST CIRCL RHEL Ubuntu

Severity

Severity Score
CVSS Version 2.x LOW 2.1
CVSS Version 3.x MEDIUM 4.4

Status

OS name Project name Version Score Severity Status Errata Last updated

Statement

CentOS 6 ELS kernel 2.6.32 4.4 MEDIUM Ignored 2022-01-27 11:19:50 Ignored due to low severity
CentOS 7 ELS kernel 3.10.0 4.4 MEDIUM Ignored 2023-09-19 09:30:11 Ignored due to low severity
CentOS 8.4 ELS kernel 4.18.0 4.4 MEDIUM Ignored 2022-02-10 08:36:37 Ignored due to low severity
CentOS 8.5 ELS kernel 4.18.0 4.4 MEDIUM Not Vulnerable 2025-10-24 07:18:43
CloudLinux 6 ELS kernel 2.6.32 4.4 MEDIUM Ignored 2022-01-27 11:19:50 Ignored due to low severity
Oracle Linux 6 ELS kernel 2.6.32 4.4 MEDIUM Ignored 2022-01-27 11:19:50 Ignored due to low severity
Ubuntu 16.04 ELS linux-hwe 4.15.0 4.4 MEDIUM Ignored 2022-09-28 05:02:36 Ignored due to low severity
Ubuntu 16.04 ELS linux 4.4.0 4.4 MEDIUM Ignored 2022-01-27 11:19:50 Ignored due to low severity
Ubuntu 18.04 ELS linux 4.15.0 4.4 MEDIUM Ignored 2023-03-02 04:04:11 Ignored due to low severity