CVE-2024-42161

MEDIUM
Published Jul 30, 2024 Modified Nov 3, 2025 CWE-908

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Avoid uninitialized value in BPF_CORE_READ_BITFIELD [Changes from V1: - Use a default branch in the switch statement to initialize `val'.] GCC warns that `val' may be used uninitialized in the BPF_CRE_READ_BITFIELD macro, defined in bpf_core_read.h as: [...] unsigned long long val; \ [...] \ switch (__CORE_RELO(s, field, BYTE_SIZE)) { \ case 1: val = *(const unsigned char *)p; break; \ case 2: val = *(const unsigned short *)p; break; \ case 4: val = *(const unsigned int *)p; break; \ case 8: val = *(const unsigned long long *)p; break; \ } \ [...] val; \ } \ This patch adds a default entry in the switch statement that sets `val' to zero in order to avoid the warning, and random values to be used in case __builtin_preserve_field_info returns unexpected values for BPF_FIELD_BYTE_SIZE. Tested in bpf-next master. No regressions.

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CVSS v3.1 Score

6.3
MEDIUM
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:H

Weakness Type (CWE)

CWE-908 CWE-908

Affected Products

Vendor Product
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel
linux linux_kernel

References

Advisories & Patches

https://git.kernel.org/stable/c/009367099eb61a4fc2af44d4eb06b6b4de7de6db https://git.kernel.org/stable/c/3364c2ed1c241989847f19cf83e3db903ce689e3 https://git.kernel.org/stable/c/7e5471b5efebc30dd0bc035cda86693a5c73d45f https://git.kernel.org/stable/c/a21d76bd0b0d39518e9a4c19f6cf7c042a974aff https://git.kernel.org/stable/c/b694989bb13ed5f166e633faa1eb0f21c6d261a6 https://git.kernel.org/stable/c/ff941a8449e712eaf7efca1a13bfb9afd3d99fc2 https://git.kernel.org/stable/c/009367099eb61a4fc2af44d4eb06b6b4de7de6db https://git.kernel.org/stable/c/3364c2ed1c241989847f19cf83e3db903ce689e3 https://git.kernel.org/stable/c/7e5471b5efebc30dd0bc035cda86693a5c73d45f https://git.kernel.org/stable/c/a21d76bd0b0d39518e9a4c19f6cf7c042a974aff https://git.kernel.org/stable/c/b694989bb13ed5f166e633faa1eb0f21c6d261a6 https://git.kernel.org/stable/c/ff941a8449e712eaf7efca1a13bfb9afd3d99fc2

Frequently Asked Questions

What is CVE-2024-42161? +
In the Linux kernel, the following vulnerability has been resolved: bpf: Avoid uninitialized value in BPF_CORE_READ_BITFIELD [Changes from V1: - Use a default branch in the switch statement to initialize `val'.] GCC warns that `val' may be used uninitialized in the BPF_CRE_READ_BITFIELD macro, defined in bpf_core_read.h as: [...] unsigned long long val; \ [...] \ switch (__CORE_RELO(s, field, BYTE_SIZE)) { \ case 1: val = *(const unsigned char *)p; break; \ case 2: val = *(const unsigned short *)p; break; \ case 4: val = *(const unsigned int *)p; break; \ case 8: val = *(const unsigned long long *)p; break; \ } \ [...] val; \ } \ This patch adds a default entry in the switch statement that sets `val' to zero in order to avoid the warning, and random values to be used in case __builtin_preserve_field_info returns unexpected values for BPF_FIELD_BYTE_SIZE. Tested in bpf-next master. No regressions. It has a CVSS v3.1 base score of 6.3 (MEDIUM).
How severe is CVE-2024-42161? +
CVE-2024-42161 has a CVSS v3.1 score of 6.3 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-2024-42161? +
CVE-2024-42161 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-2024-42161? +
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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