In the Linux kernel, the following vulnerability has been resolved:

s390: avoid using global register for currentstackpointer

Commit 30de14b1884b ("s390: currentstackpointer shouldn't be a function") made currentstackpointer a global register variable like on many other architectures. Unfortunately on s390 it uncovers old gcc bug which is fixed only since gcc-9.1 [gcc commit 3ad7fed1cc87 ("S/390: Fix PR89775. Stackpointer save/restore instructions removed")] and backported to gcc-8.4 and later. Due to this bug gcc versions prior to 8.4 generate broken code which leads to stack corruptions.

Current minimal gcc version required to build the kernel is declared as 5.1. It is not possible to fix all old gcc versions, so work around this problem by avoiding using global register variable for currentstackpointer.

A vulnerability was found in Libiberty. A heap and stack buffer overflow found in the dlanglname function in d-demangle.c leads to a denial of service.

The POWER9 backend in GNU Compiler Collection (GCC) before version 10 could optimize multiple calls of the builtindarn intrinsic into a single call, thus reducing the entropy of the random number generator. This occurred because a volatile operation was not specified. For example, within a single execution of a program, the output of every builtindarn() call may be the same.

stackprotectprologue in cfgexpand.c and stackprotectepilogue in function.c in GNU Compiler Collection (GCC) 4.1 through 8 (under certain circumstances) generate instruction sequences when targeting ARM targets that spill the address of the stack protector guard, which allows an attacker to bypass the protection of -fstack-protector, -fstack-protector-all, -fstack-protector-strong, and -fstack-protector-explicit against stack overflow by controlling what the stack canary is compared against.

Integer overflow in the new[] operator in gcc before 4.8.0 allows attackers to have unspecified impacts.