CVE-2024-47676 - Use After Free

Severity

78%

Complexity

18%

Confidentiality

98%

In the Linux kernel, the following vulnerability has been resolved: mm/hugetlb.c: fix UAF of vma in hugetlb fault pathway Syzbot reports a UAF in hugetlb_fault(). This happens because vmf_anon_prepare() could drop the per-VMA lock and allow the current VMA to be freed before hugetlb_vma_unlock_read() is called. We can fix this by using a modified version of vmf_anon_prepare() that doesn't release the VMA lock on failure, and then release it ourselves after hugetlb_vma_unlock_read().

CVSS 3.1 Base Score 7.8. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

Demo Examples

Use After Free

CWE-416

The following example demonstrates the weakness.


               
}
free(buf3R2);

Use After Free

CWE-416

The following code illustrates a use after free error:


               
}
free(ptr);
logError("operation aborted before commit", ptr);

When an error occurs, the pointer is immediately freed. However, this pointer is later incorrectly used in the logError function.

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