"An exploitable signed comparison vulnerability exists in the ARMv7 memcpy() implementation of GNU glibc 2.30.9000. Calling memcpy() (on ARMv7 targets that utilize the GNU glibc implementation) with a negative value for the 'num' parameter results in a signed comparison vulnerability. If an attacker underflows the 'num' parameter to memcpy(), this vulnerability could lead to undefined behavior such as writing to out-of-bounds memory and potentially remote code execution. Furthermore, this memcpy() implementation allows for program execution to continue in scenarios where a segmentation fault or crash should have occurred. The dangers occur in that subsequent execution and iterations of this code will be executed with this corrupted data."
It's not not clear that upstream actually agree it's a security bug.
They have not formally disputed the CVE though.
this got fixed upstream by these two commits:
found via https://sourceware.org/bugzilla/show_bug.cgi?id=25620#c25
they apply to glibc-2.30-r8 , but I could imagine glibc-2.31-r3 being the better place to backport this since 2.30 is already stable