CVE-2024-27023 md: Fix missing release of 'active_io' for flush

What is CVE-2024-27023?

CVE-2024-27023 is a medium-severity denial of service vulnerability in Linux kernel, published on 1 May 2024. 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:

md: Fix missing release of 'active_io' for flush

submit_flushes atomic_set(&mddev->flush_pending, 1); rdev_for_each_rcu(rdev, mddev) atomic_inc(&mddev->flush_pending); bi->bi_end_io = md_end_flush submit_bio(bi); /* flush io is done first */ md_end_flush if (atomic_dec_and_test(&mddev->flush_pending)) percpu_ref_put(&mddev->active_io) -> active_io is not released

if (atomic_dec_and_test(&mddev->flush_pending)) -> missing release of active_io

For consequence, mddev_suspend() will wait for 'active_io' to be zero forever.

Fix this problem by releasing 'active_io' in submit_flushes() if 'flush_pending' is decreased to zero.

Which versions are affected by CVE-2024-27023?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-27023?

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-2024-27023 being exploited?

There is no known exploitation of CVE-2024-27023 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-2024-27023, DEBIAN-CVE-2024-27023, GHSA-93q3-24jj-x39c, UBUNTU-CVE-2024-27023.