CVE-2021-22555
Linux Kernel Heap Out-of-Bounds Write Vulnerability - [Actively Exploited]
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
INFO
Published Date :
July 7, 2021, 12:15 p.m.
Last Modified :
Oct. 7, 2025, 1:45 p.m.
Remotely Exploit :
No
Source :
[email protected]
CISA KEV (Known Exploited Vulnerabilities)
For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.
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.
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
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
Affected Products
The following products are affected by CVE-2021-22555
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update the affected packages or kernel.
- Upgrade to a non-vulnerable version if available.
- Contact the vendor for further instructions if needed.
Public PoC/Exploit Available at Github
CVE-2021-22555 has a 89 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-22555.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-22555 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-22555
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Forked from https://github.com/0xor0ne/awesome-list.git
None
None
Dockerfile Shell
None
Python C Emacs Lisp Shell
一个强大的Linux漏洞搜索工具，基于原始的[Linux -exploit- suggestion](https://github.com/mzet-/linux-exploit-suggester)，专注于检测**2020-2024**期间最新的Linux内核特权升级漏洞。
Shell Python
None
C Shell Python Ruby Makefile HTML Linker Script Batchfile Perl
None
Shell
None
A comprehensive post-exploitation automation and privilege escalation Toolkit
Python C Emacs Lisp Shell
None
None
MagicLinPwn is a powerful and automated Linux privilege escalation script designed to help security professionals and CTF enthusiasts identify potential misconfigurations, vulnerabilities, and weaknesses that can lead to privilege escalation.
Shell
A collection of POCs and miscs
CodeQL Shell Python C Java Go Assembly Makefile GDB C++
PYTHA-SHELL is an educational cybersecurity tool featuring an RCE mode. It offers practical examples and demonstrations to help students understand various attacks and vulnerabilities in a controlled environment. PYTHA-SHELL provides hands-on experience with real-world security risks making it a valuable resource for learning and teaching
backdoor backdoor-attacks python pythonshell reverse-shell shell shell-script cybersecurityeducation hackingtools securitytraining vapt remotecodeexecution vulnerability-assessment cybersecurity hacking-tool
None
CodeQL Shell Python C Java Go Assembly Makefile GDB C++
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-22555 vulnerability anywhere in the article.
-
TheCyberThrone
CISA Adds 7 Actively Exploited Vulnerabilities to KEV Catalog
October 7, 2025The Cybersecurity and Infrastructure Security Agency (CISA) has expanded its Known Exploited Vulnerabilities (KEV) catalog in October 2025, adding several high-impact vulnerabilities be ... Read more
-
CybersecurityNews
Threat Actors Leveraging Windows and Linux Vulnerabilities in Real-world Attacks to Gain System Access
Cybersecurity teams worldwide have observed a surge in sophisticated campaigns exploiting both Windows and Linux vulnerabilities in recent months to achieve unauthorized system access. These attacks o ... Read more
-
Daily CyberSecurity
Kaspersky Report: Vulnerabilities Are Exploding, and Attackers Are Adapting
Kaspersky Labs has published its Q2 2025 vulnerability analysis, revealing an alarming rise in both the number of vulnerabilities registered and their exploitation in the wild. The findings show that ... Read more
-
Kaspersky
Exploits and vulnerabilities in Q2 2025
Vulnerability registrations in Q2 2025 proved to be quite dynamic. Vulnerabilities that were published impact the security of nearly every computer subsystem: UEFI, drivers, operating systems, browser ... Read more
The following table lists the changes that have been made to the
CVE-2021-22555 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Modified Analysis by [email protected]
Oct. 07, 2025
Action Type Old Value New Value Added CPE Configuration AND OR *cpe:2.3:o:netapp:c400_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:c400:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:c250_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:c250:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:h410c_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:h410c:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:h300s:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:h500s:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:h700s:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:h410s:-:*:*:*:*:*:*:* Changed CPE Configuration OR *cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:* *cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:* OR *cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:* *cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:* *cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:* *cpe:2.3:a:netapp:solidfire_baseboard_management_controller:*:*:*:*:*:*:*:* -
CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725
Oct. 07, 2025
Action Type Old Value New Value Added Date Added 2025-10-06 Added Due Date 2025-10-27 Added Required Action Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Added Vulnerability Name Linux Kernel Heap Out-of-Bounds Write Vulnerability -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html Added Reference http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html Added Reference http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html Added Reference http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html Added Reference http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html Added Reference https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21 Added Reference https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d Added Reference https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528 Added Reference https://security.netapp.com/advisory/ntap-20210805-0010/ -
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Modified Analysis by [email protected]
Mar. 31, 2022
Action Type Old Value New Value Changed Reference Type http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html No Types Assigned http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html Exploit, Third Party Advisory, VDB Entry -
CVE Modified by [email protected]
Jan. 06, 2022
Action Type Old Value New Value Added Reference http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.html [No Types Assigned] -
Modified Analysis by [email protected]
Dec. 16, 2021
Action Type Old Value New Value Changed Reference Type http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html Third Party Advisory, VDB Entry http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html Exploit, Third Party Advisory, VDB Entry Changed Reference Type http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html No Types Assigned http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html Exploit, Third Party Advisory, VDB Entry -
CVE Modified by [email protected]
Oct. 07, 2021
Action Type Old Value New Value Added Reference http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.html [No Types Assigned] -
Modified Analysis by [email protected]
Sep. 21, 2021
Action Type Old Value New Value Changed Reference Type http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html No Types Assigned http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html Third Party Advisory, VDB Entry Changed Reference Type http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html No Types Assigned http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html Exploit, Third Party Advisory, VDB Entry Changed Reference Type http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html No Types Assigned http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html Third Party Advisory, VDB Entry Changed Reference Type https://security.netapp.com/advisory/ntap-20210805-0010/ No Types Assigned https://security.netapp.com/advisory/ntap-20210805-0010/ Third Party Advisory Added CPE Configuration OR *cpe:2.3:o:brocade:fabric_operating_system:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:fas_8300_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:fas_8300:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:fas_8700_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:fas_8700:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:aff_a400_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:aff_a400:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:aff_a250_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:aff_a250:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:aff_500f_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:aff_500f:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:h610c_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:h610c:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:h610s_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:h610s:-:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:o:netapp:h615c_firmware:-:*:*:*:*:*:*:* OR cpe:2.3:h:netapp:h615c:-:*:*:*:*:*:*:* Added CPE Configuration OR *cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:* *cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:* -
CVE Modified by [email protected]
Sep. 14, 2021
Action Type Old Value New Value Added Reference http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.html [No Types Assigned] -
CVE Modified by [email protected]
Aug. 18, 2021
Action Type Old Value New Value Added Reference http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.html [No Types Assigned] -
CVE Modified by [email protected]
Aug. 05, 2021
Action Type Old Value New Value Added Reference https://security.netapp.com/advisory/ntap-20210805-0010/ [No Types Assigned] -
CVE Modified by [email protected]
Jul. 16, 2021
Action Type Old Value New Value Added Reference http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.html [No Types Assigned] -
Initial Analysis by [email protected]
Jul. 09, 2021
Action Type Old Value New Value Added CVSS V2 NIST (AV:L/AC:L/Au:N/C:P/I:P/A:P) Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Changed Reference Type https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21 No Types Assigned https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21 Mailing List, Patch, Vendor Advisory Changed Reference Type https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d No Types Assigned https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d Mailing List, Patch, Vendor Advisory Changed Reference Type https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528 No Types Assigned https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528 Exploit, Third Party Advisory Added CWE NIST CWE-787 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.19 up to (excluding) 4.4.267 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.5 up to (excluding) 4.9.267 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.10 up to (excluding) 4.14.231 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.15 up to (excluding) 4.19.188 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 4.20 up to (excluding) 5.4.113 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.5 up to (excluding) 5.10.31 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.12
Vulnerability Scoring Details
Base CVSS Score: 8.3
Base CVSS Score: 4.6
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
84.62 }} 2.21%
score
0.99286
percentile