CVE-2021-4002 Information disclosure in kernel

What is CVE-2021-4002?

CVE-2021-4002 is a medium-severity vulnerability in Debian Debian Linux, published on 3 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

A memory leak flaw in the Linux kernel's hugetlbfs memory usage was found in the way the user maps some regions of memory twice using shmget() which are aligned to PUD alignment with the fault of some of the memory pages. A local user could use this flaw to get unauthorized access to some data.

Weakness: CWE-401, CWE-459

Which versions are affected by CVE-2021-4002?

It affects 6 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Linux kernel, Oracle Communications Cloud Native Core Binding Support Function, Oracle Communications Cloud Native Core Network Exposure Function, Oracle Communications Cloud Native Core Policy.

How do I fix CVE-2021-4002?

Apply the vendor's patch.

Is CVE-2021-4002 being exploited?

There is no known exploitation of CVE-2021-4002 in the wild and no public exploit code.

Other vulnerabilities in Debian Debian Linux

• CVE-2015-3306 ProFTPD Improper Access Control Exploited Critical 10.0
• CVE-2025-49113 RoundCube Webmail Deserialization of Untrusted Data Exploited Critical 9.9
• CVE-2026-24061 GNU InetUtils Argument Injection Exploited Critical 9.8
• CVE-2025-39682 Linux Kernel Improper Check for Unusual or Exceptional Conditions Exploited Critical 9.8
• CVE-2024-9680 Mozilla Firefox Use-After-Free Exploited Critical 9.8

All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-8995, DEBIAN-CVE-2021-4002, GHSA-7jmv-5cqq-75jg, UBUNTU-CVE-2021-4002, USN-5206-1, USN-5211-1.