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.
| Software | From | Fixed in |
|---|---|---|
| gnu / glibc | - | 2.31.x |
| fedoraproject / fedora | 31 | 31.x |
| fedoraproject / fedora | 32 | 32.x |
| debian / debian_linux | 10.0 | 10.0.x |