CVE-2021-22555
CVSS v3
7.8
HIGH
EPSS Score
85.2 %
exploit probability
CISA KEV
Yes
known exploited
Exploitation
—
SSVC status
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
CISA Known Exploited Vulnerability
- Date Added
- 2025-10-06
- Patch Due Date
- 2025-10-27
- Ransomware Use
- Unknown
Technical details
- Published
- 2021-07-07
- Exploit-DB
- EDB-50135
Frequently asked questions
What is 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
Is CVE-2021-22555 actively exploited?
Yes. CVE-2021-22555 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2025-10-27.
What is the CVSS score for CVE-2021-22555?
CVE-2021-22555 has a CVSS v3 base score of 7.8 (HIGH severity).
Is CVE-2021-22555 affecting your environment?
Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.
No credit card required · 500 free checks/month · Free API key
Other 2021 vulnerabilities worth triaging
Ranked by exploit probability (EPSS).