Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: sch_htb: fix refcount leak in htb_parent_to_leaf_offload The commit ae81feb7338c ("sch_htb: fix null pointer dereference on a null new_q") fixes a NULL pointer dereference bug, but it is not correct. Because htb_graft_helper properly handles the case when new_q is NULL, and after the previous patch by skipping this call which creates an inconsistency : dev_queue->qdisc will still point to the old qdisc, but cl->parent->leaf.q will point to the new one (which will be noop_qdisc, because new_q was NULL). The code is based on an assumption that these two pointers are the same, so it can lead to refcount leaks. The correct fix is to add a NULL pointer check to protect qdisc_refcount_inc inside htb_parent_to_leaf_offload.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux Kernel | >= 5.12, < 5.12.10 |
References
- https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416Patch
- https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893Patch
- https://git.kernel.org/stable/c/2411c02d03892a5057499f8102d0cc1e0f852416Patch
- https://git.kernel.org/stable/c/944d671d5faa0d78980a3da5c0f04960ef1ad893Patch
FAQ
What is CVE-2021-47125?
CVE-2021-47125 is a vulnerability with a CVSS score of 5.5 (MEDIUM). In the Linux kernel, the following vulnerability has been resolved: sch_htb: fix refcount leak in htb_parent_to_leaf_offload The commit ae81feb7338c ("sch_htb: fix null pointer dereference on a null...
How severe is CVE-2021-47125?
CVE-2021-47125 has been rated MEDIUM with a CVSS base score of 5.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-47125?
Check the references section above for vendor advisories and patch information. Affected products include: Linux Linux Kernel.