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CVE-2021-47556 Null pointer dereference

Remediate Within 6 Months

CVE Information

Original CVE data


In the Linux kernel, the following vulnerability has been resolved: ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce() ethtool_set_coalesce() now uses both the .get_coalesce() and .set_coalesce() callbacks. But the check for their availability is buggy, so changing the coalesce settings on a device where the driver provides only _one_ of the callbacks results in a NULL pointer dereference instead of an -EOPNOTSUPP. Fix the condition so that the availability of both callbacks is ensured. This also matches the netlink code. Note that reproducing this requires some effort - it only affects the legacy ioctl path, and needs a specific combination of driver options: - have .get_coalesce() and .coalesce_supported but no .set_coalesce(), or - have .set_coalesce() but no .get_coalesce(). Here eg. ethtool doesn't cause the crash as it first attempts to call ethtool_get_coalesce() and bails out on error.

CVSS v2-
CVSS v3-
Affected Vendors

Basic Analysis

Common vulnerability metrics

Vulnerabilty type as detected by PRIOnengine

Null pointer dereference

CVSS Scores as calculated by PRIOnengine
CVSS v25
CVSS v37.5



No exploit code is reported to exist.

Active Exploitation

Vulnerability is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. See the KEV Catalog

Social Network Activity


Threat Actor Activity

No sightings of the vulnerability within threat reports.

Cybersecurity Frameworks

How the vulnerability maps against various cybersecurity frameworks

T1499 - Endpoint Denial of Service
T1498 - Network Denial of Service
T1203 - Exploitation for Client Execution
T1059 - Command and Scripting Interpreter

Compliance Impact

How the submited vulnerability affects compliance

PCI DSS v3.2.1-6.5.5 - Improper Error Handling
PCI DSS v3.2.1-6.5.2 - Buffer Overflows

Web Application Security Frameworks

Applicable if the issue likely affects a web application

WASC-19 - SQL Injection