Description
In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class handling This patch fixes a Use-After-Free vulnerability in the HFSC qdisc class handling. The issue occurs due to a time-of-check/time-of-use condition in hfsc_change_class() when working with certain child qdiscs like netem or codel. The vulnerability works as follows: 1. hfsc_change_class() checks if a class has packets (q.qlen != 0) 2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g., codel, netem) might drop packets and empty the queue 3. The code continues assuming the queue is still non-empty, adding the class to vttree 4. This breaks HFSC scheduler assumptions that only non-empty classes are in vttree 5. Later, when the class is destroyed, this can lead to a Use-After-Free The fix adds a second queue length check after qdisc_peek_len() to verify the queue wasn't emptied.
INFO
Published Date :
2025-05-02T14:16:01.905Z
Last Modified :
2025-11-03T19:55:28.428Z
Source :
Linux
AFFECTED PRODUCTS
The following products are affected by CVE-2025-37797 vulnerability.
| Vendors | Products |
|---|---|
| Debian |
|
| Linux |
|
REFERENCES
Here, you will find a curated list of external links that provide in-depth information to CVE-2025-37797.
