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Actively exploited · CISA KEV · NVD published 2021-07-07

CVE-2021-22555

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

  1. First PoC
  2. 1324 days →Metasploit
  3. 596 days →First cited attacker

Signals

Exploited in the wild
Yesadded 2025-10-06 · due 2025-10-27. An observation, not a forecast.
EPSS · 30-day forecast
79%Chance of exploitation in the next 30 days, 100th percentile of all CVEs. A forecast; KEV outranks it.
CVSS · NVD · HIGH
8.3CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
Internet exposure
not stated by sourcesNo exposure census on this CVE's dispatches.

Exploits

2 known · links only

Metasploit1

  1. Netfilter x_tables Heap OOB Write Privilege Escalation ↗

    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. Kernels up to 5.11 (including) are vulnerable. More information about vulnerable kernels is available at https://nvd.nist.gov/vuln/detail/CVE-2021-22555#vulnConfigurationsArea

    ruby · seen 2026-10-18

Exploit-DB1

  1. Linux Kernel 2.6.19 < 5.9 - 'Netfilter Local Privilege Escalation ↗

    created 2021-07-15

On the wire

0 dispatches

No dispatch on our wire has named this CVE yet.

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