CVE-2026-43393 btrfs: fix chunk map leak in btrfs_map_block() after btrfs_chunk_map_num_copies()

What is CVE-2026-43393?

CVE-2026-43393 is a medium-severity denial of service vulnerability in Linux kernel, published on 8 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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

btrfs: fix chunk map leak in btrfs_map_block() after btrfs_chunk_map_num_copies()

Fix a chunk map leak in btrfs_map_block(): if we return early with -EINVAL, we're not freeing the chunk map that we've just looked up.

Weakness: CWE-401

Which versions are affected by CVE-2026-43393?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-43393?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-43393 being exploited?

There is no known exploitation of CVE-2026-43393 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 BELL-CVE-2026-43393, DEBIAN-CVE-2026-43393, GHSA-945j-p452-jcmx, UBUNTU-CVE-2026-43393.