Actively exploited
Listed in CISA’s Known Exploited Vulnerabilities catalog since October 6, 2025.
CVE-2021-22555
Linux Kernel Heap Out-of-Bounds Write Vulnerability
Added to KEV October 6, 2025
Alert details
- Source feed
- CISA KEV
- CVE ID
- CVE-2021-22555
- CWE
- CWE-787
- Affected products
- Kernel · Linux Kernel · Linux
What happened
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.
What it means for your business
Linux Kernel is listed in CISA's Known Exploited Vulnerabilities catalog (CVE-2021-22555). 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. CISA remediation due date: 2025-10-27. If you need help checking exposure, call (864) 335-9223.
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date: October 27, 2025
Sources
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