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High 8.3Known exploited (CISA KEV)Published Jul 7, 2021
CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE
Updated under an hour ago ()
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It affects netapp c400_firmware and 20 other products. Add what you run to find out whether that includes you.
CISA lists it as known exploited since Oct 6, 2025; federal agencies had to remediate by Oct 27, 2025. Treat that date as your deadline.
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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
- 8.3 HIGH (v3.1, CNA)CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
- Weakness (CWE)
- CWE-787
- Known exploited
- Added to CISA KEV Oct 6, 2025; federal remediation due Oct 27, 2025Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- EPSS (exploitation in the next 30 days)
- 78.68% (percentile 100)
- Assigned by
- NVD analysis
- Analyzed
- Record last updated
- Dec 30, 2025
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
netapp c400_firmware netapp:c400_firmware | all versions | NVD |
netapp c250_firmware netapp:c250_firmware | all versions | NVD |
netapp h410c_firmware netapp:h410c_firmware | all versions | NVD |
netapp h300s_firmware netapp:h300s_firmware | all versions | NVD |
netapp h500s_firmware netapp:h500s_firmware | all versions | NVD |
netapp h700s_firmware netapp:h700s_firmware | all versions | NVD |
netapp h410s_firmware netapp:h410s_firmware | all versions | NVD |
linux linux_kernel linux:linux_kernel | from 2.6.19 before 4.4.267; from 4.5 before 4.9.267; from 4.10 before 4.14.231; from 4.15 before 4.19.188; from 4.20 before 5.4.113; from 5.5 before 5.10.31; from 5.11 before 5.12 | NVD |
broadcom fabric_operating_system broadcom:fabric_operating_system | all versions | NVD |
netapp fas_8300_firmware netapp:fas_8300_firmware | all versions | NVD |
netapp fas_8700_firmware netapp:fas_8700_firmware | all versions | NVD |
netapp aff_a400_firmware netapp:aff_a400_firmware | all versions | NVD |
netapp aff_a250_firmware netapp:aff_a250_firmware | all versions | NVD |
netapp aff_500f_firmware netapp:aff_500f_firmware | all versions | NVD |
netapp h610c_firmware netapp:h610c_firmware | all versions | NVD |
netapp h610s_firmware netapp:h610s_firmware | all versions | NVD |
netapp h615c_firmware netapp:h615c_firmware | all versions | NVD |
netapp cloud_backup netapp:cloud_backup | all versions | NVD |
netapp hci_management_node netapp:hci_management_node | all versions | NVD |
netapp solidfire netapp:solidfire | all versions | NVD |
netapp solidfire_baseboard_management_controller netapp:solidfire_baseboard_management_controller | all versions | NVD |
References
- https://github.com/google/security-research/security/advisories/GHSA-xxx5-8mvq-3528x-refsource-misc, exploit, third-party-advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=9fa492cdc160cd27ce1046cb36f47d3b2b1efa21x-refsource-misc, mailing-list, patch, vendor-advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/net/netfilter/x_tables.c?id=b29c457a6511435960115c0f548c4360d5f4801dx-refsource-misc, mailing-list, patch, vendor-advisory
- http://packetstormsecurity.com/files/163528/Linux-Kernel-Netfilter-Heap-Out-Of-Bounds-Write.htmlx-refsource-misc, third-party-advisory, vdb-entry
- https://security.netapp.com/advisory/ntap-20210805-0010/x-refsource-confirm, third-party-advisory
- http://packetstormsecurity.com/files/163878/Kernel-Live-Patch-Security-Notice-LSN-0080-1.htmlx-refsource-misc, exploit, third-party-advisory, vdb-entry
- http://packetstormsecurity.com/files/164155/Kernel-Live-Patch-Security-Notice-LSN-0081-1.htmlx-refsource-misc, exploit, third-party-advisory, vdb-entry
- http://packetstormsecurity.com/files/164437/Netfilter-x_tables-Heap-Out-Of-Bounds-Write-Privilege-Escalation.htmlx-refsource-misc, exploit, third-party-advisory, vdb-entry
- http://packetstormsecurity.com/files/165477/Kernel-Live-Patch-Security-Notice-LSN-0083-1.htmlx-refsource-misc, exploit, third-party-advisory, vdb-entry
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-22555us-government-resource
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.