CVE-2021-47248 udp: fix race between close() and udp_abort()

What is CVE-2021-47248?

CVE-2021-47248 is a high-severity vulnerability in Linux kernel, published on 21 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:

udp: fix race between close() and udp_abort()

Kaustubh reported and diagnosed a panic in udp_lib_lookup(). The root cause is udp_abort() racing with close(). Both racing functions acquire the socket lock, but udp{v6}_destroy_sock() release it before performing destructive actions.

We can't easily extend the socket lock scope to avoid the race, instead use the SOCK_DEAD flag to prevent udp_abort from doing any action when the critical race happens.

Diagnosed-and-tested-by: Kaustubh Pandey <[email protected]>

Weakness: CWE-362

Which versions are affected by CVE-2021-47248?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2021-47248?

Apply the vendor's patch.

Is CVE-2021-47248 being exploited?

There is no known exploitation of CVE-2021-47248 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 DEBIAN-CVE-2021-47248, GHSA-rr3f-v8j5-mmr6, UBUNTU-CVE-2021-47248.