CVE-2021-3483 - Use After Free

Severity

78%

Complexity

18%

Confidentiality

98%

A flaw was found in the Nosy driver in the Linux kernel. This issue allows a device to be inserted twice into a doubly-linked list, leading to a use-after-free when one of these devices is removed. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability. Versions before kernel 5.12-rc6 are affected

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).

CVSS 2.0 Base Score 4.6. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (AV:L/AC:L/Au:N/C:P/I:P/A:P).

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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