linux linux-kernel CVE-2021-22555 vulnerability in Linux and Other Products
Published on July 7, 2021

Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE

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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

NVD

Known Exploited Vulnerability

This Linux Kernel Heap Out-of-Bounds Write Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. 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.

The following remediation steps are recommended / required by October 27, 2025: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vulnerability Analysis

Attack Vector:
ADJACENT_NETWORK
Attack Complexity:
HIGH
Privileges Required:
NONE
User Interaction:
NONE
Scope:
CHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Weakness Type

What is a Memory Corruption Vulnerability?

The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.

CVE-2021-22555 has been classified to as a Memory Corruption vulnerability or weakness.


Products Associated with CVE-2021-22555

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Exploit Probability

EPSS
85.24%
Percentile
99.34%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.