October 21, 2026

CVE Watchtower

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CVE-2021-22555NVD

Vulnerability Summary

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
Severity Level
HIGH(8.3)
Published Date
Jul 7, 2021
Last Modified
Oct 13, 2026
PoC
Available(Metasploit)
Exploitation Status
ACTIVE
EPSS Score (30-Day)
78.68%Probability
Root Weakness (CWE)
CWE-787: Unknown/Unlisted Weakness ↗
Refer to the official MITRE database for detailed architectural specifications regarding this weakness.
CVSS v3.1 Base Metrics — Score 8.3 (HIGH)
Attack VectorAdjacent
Attack ComplexityHigh
Privileges RequiredNone
User InteractionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • Netapp C400 Firmware
  • Netapp C250 Firmware
  • Netapp H410c Firmware
  • Netapp H300s Firmware
  • Netapp H500s Firmware
  • Netapp H700s Firmware
  • Netapp H410s Firmware
  • Linux Linux Kernel >= 2.6.19 and < 4.4.267
  • Linux Linux Kernel >= 4.5 and < 4.9.267
  • Linux Linux Kernel >= 4.10 and < 4.14.231
  • Linux Linux Kernel >= 4.15 and < 4.19.188
  • Linux Linux Kernel >= 4.20 and < 5.4.113
  • Linux Linux Kernel >= 5.5 and < 5.10.31
  • Linux Linux Kernel >= 5.11 and < 5.12
  • Broadcom Fabric Operating System
  • Netapp Fas 8300 Firmware
  • Netapp Fas 8700 Firmware
  • Netapp Aff A400 Firmware
  • Netapp Aff A250 Firmware
  • Netapp Aff 500f Firmware
  • Netapp H610c Firmware
  • Netapp H610s Firmware
  • Netapp H615c Firmware
  • Netapp Cloud Backup
  • Netapp Hci Management Node
  • Netapp Solidfire
  • Netapp Solidfire Baseboard Management Controller
Patched Versions
  • Linux Linux Kernel 4.4.267
  • Linux Linux Kernel 4.9.267
  • Linux Linux Kernel 4.14.231
  • Linux Linux Kernel 4.19.188
  • Linux Linux Kernel 5.4.113
  • Linux Linux Kernel 5.10.31
  • Linux Linux Kernel 5.12
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🔀Smart Routing — Critical alerts to one channel, rest to another.
🚫Ad-Free — Uninterrupted experience.
🎁7-Day Free Trial — Try Pro or Team, no card required.
📧Email Delivery — Threat intel straight to your inbox.
♾️Unlimited Vendors — Track your entire stack.
🚨All New CVEs — Be the first to know.
📈EPSS Spike Alerts — Catch rising risk before it peaks.
🎯Custom EPSS/CVSS — Filter noise, focus on risk.
🛡️Exploit Intel — A 2nd confirmed-exploit signal beyond KEV.
🐙GitHub Issues — Auto-tracked, no duplicates.
📬Weekly Digest — One clean summary, not inbox spam.
🏷️Watchlist Groups — Tag alerts by team (Infra/AppSec/SOC).
💬Webhooks — Slack & Teams integration.
🔀Smart Routing — Critical alerts to one channel, rest to another.
🚫Ad-Free — Uninterrupted experience.

External References