The daemon in GDM through 3.29.1 does not properly unexport display objects from its D-Bus interface when they are destroyed, which allows a local attacker to trigger a use-after-free via a specially crafted sequence of D-Bus method calls, resulting in a denial of service or potential code execution.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
| Link | Tags |
|---|---|
| https://lists.debian.org/debian-lts-announce/2018/09/msg00003.html | mailing list |
| https://gitlab.gnome.org/GNOME/gdm/issues/401 | third party advisory |
| https://usn.ubuntu.com/3737-1/ | third party advisory vendor advisory |
| https://www.debian.org/security/2018/dsa-4270 | third party advisory vendor advisory |
| http://www.securityfocus.com/bid/105179 | third party advisory vdb entry |