CVE-2024-26718 dm-crypt, dm-verity: disable tasklets

What is CVE-2024-26718?

CVE-2024-26718 is a high-severity memory corruption vulnerability in Linux kernel, published on 3 Apr 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:

dm-crypt, dm-verity: disable tasklets

Tasklets have an inherent problem with memory corruption. The function tasklet_action_common calls tasklet_trylock, then it calls the tasklet callback and then it calls tasklet_unlock. If the tasklet callback frees the structure that contains the tasklet or if it calls some code that may free it, tasklet_unlock will write into free memory.

The commits 8e14f610159d and d9a02e016aaf try to fix it for dm-crypt, but it is not a sufficient fix and the data corruption can still happen [1]. There is no fix for dm-verity and dm-verity will write into free memory with every tasklet-processed bio.

There will be atomic workqueues implemented in the kernel 6.9 [2]. They will have better interface and they will not suffer from the memory corruption problem.

But we need something that stops the memory corruption now and that can be backported to the stable kernels. So, I'm proposing this commit that disables tasklets in both dm-crypt and dm-verity. This commit doesn't remove the tasklet support, because the tasklet code will be reused when atomic workqueues will be implemented.

[1] https://lore.kernel.org/all/[email protected]/T/ [2] https://lore.kernel.org/lkml/[email protected]/

Weakness: CWE-787

Which versions are affected by CVE-2024-26718?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-26718?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2024-26718 being exploited?

There is no known exploitation of CVE-2024-26718 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 AZL-58746, BELL-CVE-2024-26718, DEBIAN-CVE-2024-26718, GHSA-5qvv-jjxx-82r8, ROOT-OS-DEBIAN-11-CVE-2024-26718, UBUNTU-CVE-2024-26718.