CVE-2024-42161

CVE-2024-42161 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 6.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-908.

Key facts

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.

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.
How severe is CVE-2024-42161?
CVE-2024-42161 has a CVSS 3.x base score of 6.3, rated medium severity. It is exploitable over local access with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability high.
Is CVE-2024-42161 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2024-42161?
CVE-2024-42161 affects Linux Linux Kernel. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2024-42161?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2024-42161 have an EU (EUVD) identifier?
Yes. CVE-2024-42161 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2024-39992.
When was CVE-2024-42161 published?
CVE-2024-42161 was published on 2024-07-30 and last updated on 2026-06-17.

References

Affected products (1)

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