CVE-2025-37992: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-37992 is a vulnerability discovered in the Linux kernel's network scheduling (netsched) component, published on May 26, 2025. The vulnerability affects multiple queue disciplines (qdiscs) including codel, fq, fqcodel, fqpie, hhf, and pie (Wiz Database).

The vulnerability occurs when reducing a qdisc's limit via the ->change() operation, where only the main skb queue was being trimmed, potentially leaving packets in the gso_skb list. This could result in a NULL pointer dereference when checking sch->limit against sch->q.qlen (NVD).

The vulnerability could lead to NULL pointer dereferences in the Linux kernel's network scheduling component, potentially causing system instability or crashes (Wiz Database).

A patch has been implemented that introduces a new helper function called qdiscdequeueinternal(), which ensures both the gso_skb list and the main queue are properly flushed when trimming excess packets. All affected qdiscs have been updated to use this new helper in their ->change() routines. The fix is available in version 6.1.140-1 for Debian bookworm and 6.12.30-1 for Debian sid (Debian Tracker).