CVE-2021-22555

HIGH CISA KEV

Published Jul 7, 20214y ago · Modified Jun 17, 20262w ago

7.8 CVSS 3.1

High

Find Similar

Published Jul 7, 2021 4y ago

Last Modified Jun 17, 2026 2w ago

KEV Listed Oct 6, 2025 9mo ago

KEV Due Oct 27, 2025 251d overdue

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

CVSS Details

Base Score

7.8

Exploitability

1.8

Impact

5.9

Vector string

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

Attack Vector Local

Attack Complexity Low

Privileges Required Low

User Interaction None

Scope Unchanged

Confidentiality High

Integrity High

Availability High

Threat Intelligence

CISA Known Exploited Overdue 251d

Added: Oct 6, 2025
Due: Oct 27, 2025

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Exploit & Patch Status

Actively Exploited (KEV)

Patch Available

Weaknesses 1

CWE-787 Out-of-bounds Write Memory Safety

Affected Products 42

Vendor	Product	Version	Range
netapp	c400_firmware	*	any
netapp	c400	*	any
netapp	c250_firmware	*	any
netapp	c250	*	any
netapp	h410c_firmware	*	any
netapp	h410c	*	any
netapp	h300s_firmware	*	any
netapp	h300s	*	any
netapp	h500s_firmware	*	any
netapp	h500s	*	any
netapp	h700s_firmware	*	any
netapp	h700s	*	any
netapp	h410s_firmware	*	any
netapp	h410s	*	any
linux	linux_kernel	*	≥2.6.19 – <4.4.267
linux	linux_kernel	*	≥4.5 – <4.9.267
linux	linux_kernel	*	≥4.10 – <4.14.231
linux	linux_kernel	*	≥4.15 – <4.19.188
linux	linux_kernel	*	≥4.20 – <5.4.113
linux	linux_kernel	*	≥5.5 – <5.10.31
linux	linux_kernel	*	≥5.11 – <5.12
brocade	fabric_operating_system	*	any
netapp	fas_8300_firmware	*	any
netapp	fas_8300	*	any
netapp	fas_8700_firmware	*	any
netapp	fas_8700	*	any
netapp	aff_a400_firmware	*	any
netapp	aff_a400	*	any
netapp	aff_a250_firmware	*	any
netapp	aff_a250	*	any
netapp	aff_500f_firmware	*	any
netapp	aff_500f	*	any
netapp	h610c_firmware	*	any
netapp	h610c	*	any
netapp	h610s_firmware	*	any
netapp	h610s	*	any
netapp	h615c_firmware	*	any
netapp	h615c	*	any
netapp	cloud_backup	*	any
netapp	hci_management_node	*	any
netapp	solidfire	*	any
netapp	solidfire_baseboard_management_controller	*	any

References 10

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

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

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

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

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

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

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

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

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

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

US Government Resource

Remediation

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

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

Mailing ListPatchVendor Advisory