CVE-2023-4389 - Use After Free

Severity

71%

Complexity

18%

Confidentiality

86%

A flaw was found in btrfs_get_root_ref in fs/btrfs/disk-io.c in the btrfs filesystem in the Linux Kernel due to a double decrement of the reference count. This issue may allow a local attacker with user privilege to crash the system or may lead to leaked internal kernel information.

CVSS 3.1 Base Score 7.1. 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:N/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.

Demo Examples

Double Free

CWE-415

Double Free

CWE-415

While contrived, this code should be exploitable on Linux distributions which do not ship with heap-chunk check summing turned on.


               
}
free(buf1R2);

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