CVE-2024-49987: linux kernel Null Dereference — Fix

Description

In the Linux kernel, the following vulnerability has been resolved: bpftool: Fix undefined behavior in qsort(NULL, 0, ...) When netfilter has no entry to display, qsort is called with qsort(NULL, 0, ...). This results in undefined behavior, as UBSan reports: net.c:827:2: runtime error: null pointer passed as argument 1, which is declared to never be null Although the C standard does not explicitly state whether calling qsort with a NULL pointer when the size is 0 constitutes undefined behavior, Section 7.1.4 of the C standard (Use of library functions) mentions: "Each of the following statements applies unless explicitly stated otherwise in the detailed descriptions that follow: If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, or a pointer to non-modifiable storage when the corresponding parameter is not const-qualified) or a type (after promotion) not expected by a function with variable number of arguments, the behavior is undefined." To avoid this, add an early return when nf_link_info is NULL to prevent calling qsort with a NULL pointer.

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CVSS v3.1 Score

5.5

MEDIUM

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

Weakness Type (CWE)

CWE-476 CWE-476

Affected Products

Vendor	Product	Versions
linux	linux_kernel	< 6.6.55
linux	linux_kernel	6.7 — 6.10.14
linux	linux_kernel	6.11 — 6.11.3

References

Advisories & Patches

https://git.kernel.org/stable/c/2e0f6f33f2aa87493b365a38a8fd87b8854b7734 https://git.kernel.org/stable/c/c208b02827eb642758cef65641995fd3f38c89af https://git.kernel.org/stable/c/c2d9f9a7837ab29ccae0c42252f17d436bf0a501 https://git.kernel.org/stable/c/f04e2ad394e2755d0bb2d858ecb5598718bf00d5

Frequently Asked Questions

What is CVE-2024-49987? +

In the Linux kernel, the following vulnerability has been resolved: bpftool: Fix undefined behavior in qsort(NULL, 0, ...) When netfilter has no entry to display, qsort is called with qsort(NULL, 0, ...). This results in undefined behavior, as UBSan reports: net.c:827:2: runtime error: null pointer passed as argument 1, which is declared to never be null Although the C standard does not explicitly state whether calling qsort with a NULL pointer when the size is 0 constitutes undefined behavior, Section 7.1.4 of the C standard (Use of library functions) mentions: "Each of the following statements applies unless explicitly stated otherwise in the detailed descriptions that follow: If an argument to a function has an invalid value (such as a value outside the domain of the function, or a pointer outside the address space of the program, or a null pointer, or a pointer to non-modifiable storage when the corresponding parameter is not const-qualified) or a type (after promotion) not expected by a function with variable number of arguments, the behavior is undefined." To avoid this, add an early return when nf_link_info is NULL to prevent calling qsort with a NULL pointer. It has a CVSS v3.1 base score of 5.5 (MEDIUM).

How severe is CVE-2024-49987? +

CVE-2024-49987 has a CVSS v3.1 score of 5.5 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2024-49987? +

CVE-2024-49987 affects products from linux, specifically: linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2024-49987? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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