Linux · Linux Kernel · CVE-2021-47515
Name of the Vulnerable Software and Affected Versions:
Linux kernel versions prior to 5.16-rc4
Description:
The issue is related to a NULL pointer dereference in the seg6 component of the Linux kernel. When an IPv4 packet is received and meant to be encapsulated in an outer IPv6+SRH header, the seg6 do srh encap function clears the IPv6 socket control block, leading to a loss of receiving interface index information. This condition can trigger a NULL pointer dereference if a specific commit is applied. The vulnerability can be exploited to cause a denial of service.
Recommendations:
To resolve the issue, update the Linux kernel to a version that includes the fix for the seg6 component, specifically the change that sets the IP6CB(skb)->iif with the index of the receiving interface once again.
At the moment, there is no information about a newer version that contains a fix for this vulnerability.