CVE-2009-4021 Null dereference in n/a

What is CVE-2009-4021?

CVE-2009-4021 is a medium-severity vulnerability in Linux kernel, published on 25 Nov 2009. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

The fuse_direct_io function in fs/fuse/file.c in the fuse subsystem in the Linux kernel before 2.6.32-rc7 might allow attackers to cause a denial of service (invalid pointer dereference and OOPS) via vectors possibly related to a memory-consumption attack.

Weakness: CWE-399

Which versions are affected by CVE-2009-4021?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2009-4021?

Upgrade to a fixed version.

Is CVE-2009-4021 being exploited?

There is no known exploitation of CVE-2009-4021 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

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

Also known as GHSA-fc2m-v5px-4xvc.