CVE-2021-22555
high CISA KEVLinux Kernel Heap Out-of-Bounds Write Vulnerability
Vendor / product: Linux — Kernel
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
7.8
7.8 (CVSS v3.1)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2021-07-07 12:15
Modified: 2026-10-13 18:25
NVD status: Analyzed
Last synced 1 day ago
Verified against the source API 2026-10-27 07:07 UTC
Exploitation
Listed in CISA KEV
Added 2025-10-06 · due 2025-10-27
Known ransomware use: Unknown
Required action (CISA)
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Affected products
netapp / c400_firmware all versions
netapp / c250_firmware all versions
netapp / h410c_firmware all versions
netapp / h300s_firmware all versions
netapp / h500s_firmware all versions
netapp / h700s_firmware all versions
netapp / h410s_firmware all versions
linux / linux_kernel ≥2.6.19 <4.4.267, ≥4.5 <4.9.267, ≥4.10 <4.14.231, ≥4.15 <4.19.188, ≥4.20 <5.4.113, ≥5.5 <5.10.31
broadcom / fabric_operating_system all versions
netapp / fas_8300_firmware all versions
netapp / fas_8700_firmware all versions
netapp / aff_a400_firmware all versions
netapp / aff_a250_firmware all versions
netapp / aff_500f_firmware all versions
netapp / h610c_firmware all versions
netapp / h610s_firmware all versions
netapp / h615c_firmware all versions
netapp / cloud_backup all versions
netapp / hci_management_node all versions
netapp / solidfire all versions
netapp / solidfire_baseboard_management_controller all versions
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21
Vendor advisory: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d
Vendor advisory: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21
Vendor advisory: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d
Patch / mitigation: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21
Patch / mitigation: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801d
References
- http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Writ... cve-coordination@google.com
- http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.h... cve-coordination@google.com
- http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.h... cve-coordination@google.com
- http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Pr... cve-coordination@google.com
- http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.h... cve-coordination@google.com
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_... cve-coordination@google.com
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_... cve-coordination@google.com
- https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528 cve-coordination@google.com
- https://security.netapp.com/advisory/ntap-20210805-0010/ cve-coordination@google.com
- http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Writ... af854a3a-2127-422b-91ae-364da2661108
- http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.h... af854a3a-2127-422b-91ae-364da2661108
- http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.h... af854a3a-2127-422b-91ae-364da2661108
- http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Pr... af854a3a-2127-422b-91ae-364da2661108
- http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.h... af854a3a-2127-422b-91ae-364da2661108
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_... af854a3a-2127-422b-91ae-364da2661108
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_... af854a3a-2127-422b-91ae-364da2661108
- https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528 af854a3a-2127-422b-91ae-364da2661108
- https://security.netapp.com/advisory/ntap-20210805-0010/ af854a3a-2127-422b-91ae-364da2661108
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22555 134c704f-9b21-4f2e-91b3-4a467353bcc0
Data sources
CISA KEV — fetched 2026-10-27 06:50 UTC · record ↗
NVD CVE API 2.0 — fetched 2026-10-27 07:07 UTC · record ↗