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CVE-2021-47218

5.5 · MEDIUM

In the Linux kernel, the following vulnerability has been resolved: selinux: fix NULL-pointer dereference when hashtab allocation fails When the hash table slot array allocation fails in hashtab_…

Published Apr 10, 2024CWE-476EPSS 0.22%

Overview

CVE-2021-47218 is a medium-severity vulnerability. It was published on April 10, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

selinux: fix NULL-pointer dereference when hashtab allocation fails

When the hash table slot array allocation fails in hashtab_init(),

h->size is left initialized with a non-zero value, but the h->htable

pointer is NULL. This may then cause a NULL pointer dereference, since

the policydb code relies on the assumption that even after a failed

hashtab_init(), hashtab_map() and hashtab_destroy() can be safely called

on it. Yet, these detect an empty hashtab only by looking at the size.

Fix this by making sure that hashtab_init() always leaves behind a valid

empty hashtab when the allocation fails.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/83c8ab8503adf56bf68dafc7a382f4946c87da79Refgit.kernel.org/stable/c/b17dd53cac769dd13031b0ca34f90cc65e523fabRefgit.kernel.org/stable/c/dc27f3c5d10c58069672215787a96b4fae01818bRefgit.kernel.org/stable/c/83c8ab8503adf56bf68dafc7a382f4946c87da79Refgit.kernel.org/stable/c/b17dd53cac769dd13031b0ca34f90cc65e523fabRefgit.kernel.org/stable/c/dc27f3c5d10c58069672215787a96b4fae01818b

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47218?

CVE-2021-47218 is a medium-severity vulnerability. It was published on April 10, 2024 and has a CVSS 3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2021-47218?

This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47218?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47218?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47218 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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