Description

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

net: explicitly clear the sk pointer, when pf->create fails

We have recently noticed the exact same KASAN splat as in commit
6cd4a78d962b ("net: do not leave a dangling sk pointer, when socket
creation fails"). The problem is that commit did not fully address the
problem, as some pf->create implementations do not use sk_common_release
in their error paths.

For example, we can use the same reproducer as in the above commit, but
changing ping to arping. arping uses AF_PACKET socket and if packet_create
fails, it will just sk_free the allocated sk object.

While we could chase all the pf->create implementations and make sure they
NULL the freed sk object on error from the socket, we can't guarantee
future protocols will not make the same mistake.

So it is easier to just explicitly NULL the sk pointer upon return from
pf->create in __sock_create. We do know that pf->create always releases the
allocated sk object on error, so if the pointer is not NULL, it is
definitely dangling.

Classification

CVE ID: CVE-2024-50186

CVSS Base Severity: HIGH

CVSS Base Score: 7.8

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.03% (probability of being exploited)

EPSS Percentile: 5.24% (scored less or equal to compared to others)

EPSS Date: 2025-06-02 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2024-50186
https://git.kernel.org/stable/c/daf462ff3cde6ecf22b98d9ae770232c10d28de2
https://git.kernel.org/stable/c/b7d22a79ff4e962b8af5ffe623abd1d6c179eb9f
https://git.kernel.org/stable/c/563e6892e21d6ecabdf62103fc4e7b326d212334
https://git.kernel.org/stable/c/8e1b72fd74bf9da3b099d09857f4e7f114f38e12
https://git.kernel.org/stable/c/631083143315d1b192bd7d915b967b37819e88ea

Timeline