CVE-2021-20239

A flaw was found in the Linux kernel in versions before 5.4.92 in the BPF protocol. This flaw allows an attacker with a local account to leak information about kernel internal addresses. The highest threat from this vulnerability is to confidentiality.

Weakness

The product obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer.

Affected Software

Extended Description

An attacker can supply a pointer for memory locations that the product is not expecting. If the pointer is dereferenced for a write operation, the attack might allow modification of critical state variables, cause a crash, or execute code. If the dereferencing operation is for a read, then the attack might allow reading of sensitive data, cause a crash, or set a variable to an unexpected value (since the value will be read from an unexpected memory location). There are several variants of this weakness, including but not necessarily limited to:

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/129.html

References

• https://bugzilla.redhat.com/show_bug.cgi?id=1923636
• https://bugzilla.redhat.com/show_bug.cgi?id=1923636