CVE-2021-47624: net/sunrpc: fix reference count leaks in rpc_sysfs_xprt_state_change
In the Linux kernel, the following vulnerability has been resolved:
net/sunrpc: fix reference count leaks in rpcsysfsxprtstatechange
The refcount leak issues take place in an error handling path. When the 3rd argument buf doesn't match with "offline", "online" or "remove", the function simply returns -EINVAL and forgets to decrease the reference count of a rpcxprt object and a rpcxprtswitch object increased by rpcsysfsxprtkobjgetxprt() and rpcsysfsxprtkobjgetxprtswitch(), causing reference count leaks of both unused objects.
Fix this issue by jumping to the error handling path labelled with output when buf matches none of "offline", "online" or "remove".
Other sources
Linux Kernel is vulnerable to a denial of service, caused by reference count leaks in rpcsysfsxprtstatechange. An attacker could exploit this vulnerability to cause a denial of service.
— IBM
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2021-47624?
CVE-2021-47624 is classified as a medium severity vulnerability due to its impact on the Linux kernel's reference counting mechanism.
How do I fix CVE-2021-47624?
To mitigate CVE-2021-47624, upgrade to kernel versions 5.15.24, 5.16.10, or 5.17 as specified in the advisory.
What systems are impacted by CVE-2021-47624?
CVE-2021-47624 affects Linux kernel versions prior to 5.15.24, 5.16.10, and 5.17.
What is the nature of the vulnerability in CVE-2021-47624?
CVE-2021-47624 involves reference count leaks in the error handling path of the net/sunrpc component.
Are there any workarounds for CVE-2021-47624?
There are no recommended workarounds for CVE-2021-47624; the proper solution is to apply the appropriate kernel updates.