A use-after-free vulnerability in the Linux kernel's net/sched: sch_hfsc (HFSC qdisc traffic control) component can be exploited to achieve local privilege escalation. If a class with a link-sharing curve (i.e. with the HFSC_FSC flag set) has a parent without a link-sharing curve, then init_vf() will call vttree_insert() on the parent, but vttree_remove() will be skipped in update_vf(). This leaves a dangling pointer that can cause a use-after-free. We recommend upgrading past commit b3d26c5702c7d6c45456326e56d2ccf3f103e60f.
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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b3d26c5702c7d6c45456326e56d2ccf3f103e60f | patch mailing list vendor advisory issue tracking |
| https://kernel.dance/b3d26c5702c7d6c45456326e56d2ccf3f103e60f | patch vendor advisory |
| https://lists.debian.org/debian-lts-announce/2023/10/msg00027.html | third party advisory mailing list |
| http://packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.html | third party advisory vdb entry |
| https://lists.debian.org/debian-lts-announce/2024/01/msg00004.html | third party advisory mailing list |