CISA Known Exploited Vulnerability

This vulnerability is actively exploited in the wild and listed in the CISA Known Exploited Vulnerabilities catalog.

Remediation Deadline: Oct 27, 2025

CVE-2021-22555

High

EPSS 85.2%CISA KEV

Description

Linux Kernel contains a heap out-of-bounds write vulnerability that could allow an attacker to gain privileges or cause a DoS (via heap memory corruption) through user name space.

EPSS — Exploit Probability

85.2%

Higher than 99.3% of all CVEs

Required Action

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21 ; https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d ; https://security.netapp.com/advisory/ntap-20210805-0010/ ; https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528 ; https://nvd.nist.gov/vuln/detail/CVE-2021-22555

Risk Assessment

HIGH

In CISA KEV

High EPSS

Details

Severity: High
EPSS: 85.2%
CISA KEV: Yes
Ransomware: Unknown
Articles: 0

Timeline

Published

Oct 6, 2025

Added to KEV

Oct 6, 2025

Remediation Due

Oct 27, 2025

Affected Product

Linux

Kernel

View all Linux CVEs

External Links

NVD (NIST)CVE Details MITRE CVE