CSIRTS // UNIFIED SECURITY ADVISORY FEEDSYS ● ONLINE · POWERED BY INTELFUSIONS.COM

← Back to feed

CVE-2021-22555: Linux Kernel Heap Out-of-Bounds Write Vulnerability

criticalknown exploitedpublic exploitCVE-2021-22555
Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.
Linux Kernel contains a heap out-of-bounds write vulnerability that could allow an attacker to gain privileges or cause a DoS (via heap memory corruption) through user name space.

CSIRTS triage

vendor: Linuxproduct: KernelPrivilege escalationDenial of service
What
Linux Kernel contains a heap out-of-bounds write vulnerability that could allow an attacker to gain privileges or cause a DoS.
Who is affected
Deployments of the Linux Kernel.
Urgency
Immediate remediation is necessary due to active exploitation and critical severity.
Action
Update to the latest version of the Linux Kernel.

AI-assisted analysis generated from the source advisory — verify against the original.

⚡ Watch Kernel

Get an email when a new Kernel advisory drops — max one per day, one-click unsubscribe.

Details

Source
CISA Known Exploited Vulnerabilities (US · database · site)
Severity
critical
Published
2025-10-06
Exploitation
Observed in the wild (CISA KEV)

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2021-22555

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2021-22555coverage & exploitation statusNVD · CVE.org

Recent advisories for Linux Kernel Heap

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

More from CISA Known Exploited Vulnerabilities