CVE-2024-49936 net/xen-netback: prevent UAF in xenvif_flush_hash()

What is CVE-2024-49936?

CVE-2024-49936 is a high-severity use after free vulnerability in Linux kernel, published on 21 Oct 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:

net/xen-netback: prevent UAF in xenvif_flush_hash()

During the list_for_each_entry_rcu iteration call of xenvif_flush_hash, kfree_rcu does not exist inside the rcu read critical section, so if kfree_rcu is called when the rcu grace period ends during the iteration, UAF occurs when accessing head->next after the entry becomes free.

Therefore, to solve this, you need to change it to list_for_each_entry_safe.

Weakness: CWE-416

Which versions are affected by CVE-2024-49936?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2024-49936?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2024-49936 being exploited?

There is no known exploitation of CVE-2024-49936 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-51456, BELL-CVE-2024-49936, DEBIAN-CVE-2024-49936, GHSA-vp2p-wqj6-25wf, UBUNTU-CVE-2024-49936.