CVE-2020-10711

A NULL pointer dereference flaw was found in the Linux kernel’s SELinux
subsystem in versions before 5.7. This flaw occurs while importing the
Commercial IP Security Option (CIPSO) protocol’s category bitmap into the
SELinux extensible bitmap via the’ ebitmap_netlbl_import’ routine. While
processing the CIPSO restricted bitmap tag in the ‘cipso_v4_parsetag_rbm’
routine, it sets the security attribute to indicate that the category
bitmap is present, even if it has not been allocated. This issue leads to a
NULL pointer dereference issue while importing the same category bitmap
into SELinux. This flaw allows a remote network user to crash the system
kernel, resulting in a denial of service.

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