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. Reference: https://sourceware.org/bugzilla/show_bug.cgi?id=25620
Created glibc tracking bugs for this issue: Affects: fedora-all [bug 1820332]
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2020-6096
Statement: Red Hat Enterprise Linux only supports the 64-bit ARM architecture (AArch64) which does not include the vulnerable implementation of `memcpy()`. Therefore, all versions of glibc as shipped with RHEL are not affected by this flaw.
External References: https://sourceware.org/bugzilla/attachment.cgi?id=12334
Upstream fix: https://sourceware.org/git/?p=glibc.git;a=commit;h=79a4fa341b8a89cb03f84564fd72abaa1a2db394 https://sourceware.org/git/?p=glibc.git;a=commit;h=beea361050728138b82c57dda0c4810402d342b9