Detections
Analytics

CVE-2021-22555

high

Description

A heap out-of-bounds write affecting Linux since v2.6.19-rc1 was discovered in net/netfilter/x_tables.c. This allows an attacker to gain privileges or cause a DoS (via heap memory corruption) through user name space

References

https://security.netapp.com/advisory/ntap-20210805-0010/

http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html

https://securelist.com/vulnerabilities-and-exploits-in-q2-2026/121091/

https://securelist.com/vulnerabilities-and-exploits-in-q3-2025/118197/

https://securityaffairs.com/183049/security/u-s-cisa-adds-oracle-mozilla-microsoft-windows-linux-kernel-and-microsoft-ie-flaws-to-its-known-exploited-vulnerabilities-catalog.html

https://www.cisa.gov/news-events/alerts/2025/10/06/cisa-adds-seven-known-exploited-vulnerabilities-catalog

https://securelist.com/vulnerabilities-and-exploits-in-q2-2025/117333/

https://github.com/WhatsWrongAndWhy/CVE-2021-22555

https://github.com/OleksandrBlack/cve_centos

https://github.com/nanhang-950/Kernel-Exploit

https://github.com/Su1ph3r/Cepheus

https://github.com/talent-x90c/cve_list

https://github.com/XiaozaYa/CVE-Recording

https://github.com/Ha0-Y/kernel-exploit-cve

https://github.com/Ha0-Y/LinuxKernelExploits

https://github.com/arttnba3/Linux-kernel-exploitation

https://github.com/masjohncook/netsec-project

https://github.com/veritas501/CVE-2021-22555-PipeVersion

https://github.com/xyjl-ly/CVE-2021-22555-Exploit

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22555

https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21

http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html

http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html

http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html

http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html

Details

Source: Mitre, NVD

Published: 2021-07-07

Updated: 2026-06-17

Known Exploited Vulnerability (KEV)

Risk Information

CVSS v2

Base Score: 4.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:P/A:P

Severity: Medium

CVSS v3

Base Score: 7.8

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Severity: High

EPSS

EPSS: 0.78684