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CVE-2021-22555

Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE

Basic Information

CVE State
PUBLISHED
Reserved Date
January 05, 2021
Published Date
July 07, 2021
Last Updated
December 30, 2025
Vendor
n/a
Product
Linux Kernel
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
Tags
cisa

CVSS Scores

CVSS v3.1

8.3 - HIGH

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

SSVC Information

Exploitation
active
Technical Impact
total

Exploit Status

Exploited in the Wild
Yes (2026-06-01 13:30:37 UTC) Source
Proof of Concept Available
Yes (added 2021-07-16 01:54:01 UTC) Source

References

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=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html https://security.netapp.com/advisory/ntap-20210805-0010/ http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html

Known Exploited Vulnerability Information

Source Added Date
CVE 2026-06-01 10:41:42 UTC

Scanner Integrations

Scanner URL Date Detected
Metasploit https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/local/netfilter_xtables_heap_oob_write_priv_esc.rb 2025-04-28 15:02:13 UTC

Potential Proof of Concepts

Warning: These PoCs have not been tested and could contain malware. Use at your own risk.

netfilter_xtables_heap_oob_write_priv_esc

Type: metasploit • Created: Unknown

Metasploit module for CVE-2021-22555

letsr00t/-2021-LOCALROOT-CVE-2021-22555

Type: github • Created: 2024-02-05 07:05:13 UTC • Stars: 0

pashayogi/CVE-2021-22555

Type: github • Created: 2023-08-20 14:26:28 UTC • Stars: 0

Linux Kernel 2.6.19 < 5.9 - 'Netfilter Local Privilege Escalation'

tukru/CVE-2021-22555

Type: github • Created: 2023-08-05 18:56:18 UTC • Stars: 3

This repo hosts TUKRU's Linux Privilege Escalation exploit (CVE-2021-22555). It demonstrates gaining root privileges via a vulnerability. Tested on Ubuntu 5.8.0-48-generic and COS 5.4.89+. Use responsibly and ethically.

veritas501/CVE-2021-22555-PipeVersion

Type: github • Created: 2022-04-05 06:35:25 UTC • Stars: 36

CVE-2021-22555 exploit rewritten with pipe primitive

xyjl-ly/CVE-2021-22555-Exploit

Type: github • Created: 2021-07-16 01:54:01 UTC • Stars: 10

CVE-2021-22555 Exploit

Timeline

  • CVE ID Reserved

  • CVE Published to Public

  • Proof of Concept Exploit Available

  • Detected by Metasploit

  • Added to KEVIntel