Linux · Linux Kernel · CVE-2021-47557
Name of the Vulnerable Software and Affected Versions:
Linux kernel versions prior to 5.16.0-rc1+ #475
Description:
The issue is related to a NULL pointer dereference in the Linux kernel's sch ets component. When the number of DRR classes decreases, the round-robin active list can contain elements that have already been freed in ets qdisc change(), leading to a NULL dereference crash. This is caused by the attempt to call cl->qdisc->ops->peek(cl->qdisc) when cl->qdisc is NULL.
Recommendations:
At the moment, there is no information about a newer version that contains a fix for this vulnerability.