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  4. CVE 2021 22555 heap out of bounds write in netfilter
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Back to active CVEs
High ยท CVSS 8.3Known ExploitedCVE-2021-22555

Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACECVE-2021-22555

Answer in brief

CVE-2021-22555 records a High severity (CVSS 8.3) vulnerability in Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE. The current sources mark it as known exploited. The current feed maps n/a/Linux Kernel (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 7, 2021Updated Oct 13, 2026Source checked Nov 4, 2026First seen by HOL May 24, 2026Material review Oct 13, 2026
Upstream Advisory

Key facts

Risk
High ยท CVSS 8.3
Exploitation
Known exploited
Affected software
37 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 8.3. Known-exploitation status makes exposure review time-sensitive. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps n/a/Linux Kernel (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:a:netapp:solidfire_baseboard_management_controller:*:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:aff_500f:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:aff_a250:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:aff_a400:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:c250:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:c400:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:fas_8300:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:fas_8700:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:h300s:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:h410c:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:h410s:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:h500s:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:h610c:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:h610s:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:h615c:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:h:netapp:h700s:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:broadcom:fabric_operating_system:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:aff_500f_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:aff_a250_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:aff_a400_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:c250_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:c400_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:fas_8300_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:fas_8700_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:h410c_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:h610c_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:h610s_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:h615c_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
n/a/Linux Kernelgeneric>=2.6.19-rc1 <unspecifiedunspecified

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for n/a/Linux Kernel.
  2. 2Review the reported fix. Update n/a/Linux Kernel to unspecified if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Jul 7, 2021

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 13, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    May 24, 2026

  4. Added to CISA KEV

    Oct 6, 2025

    Evidence: source:kev:kev:kev:record

Sources and claim methodology

  • Source referencepacketstormsecurity.com
  • Source referencepacketstormsecurity.com
  • Source referencepacketstormsecurity.com
  • Source referencepacketstormsecurity.com
  • Source referencepacketstormsecurity.com
  • GitHub security advisorygithub.com
  • Source referencegit.kernel.org
  • Source referencegit.kernel.org
  • Source referencesecurity.netapp.com
  • CISA Known Exploited Vulnerabilities catalogcisa.gov
Upstream source 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

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Git for Windows: git-credential-wincred OAuth Store Heap OverflowAlso CWE-787
  • Git for Windows: git-credential-wincred Erase Path Heap OverflowAlso CWE-787

Record context

Vulnerability class
Memory Corruption
EPSS
Not reported
CWE IDs
CWE-787
Source
CVE List V5
Source checked
Nov 4, 2026
References
10 linked sources
Open source record