Bug 2368609 (CVE-2025-37992)

Summary: CVE-2025-37992 kernel: net_sched: Flush gso_skb list too during ->change()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-05-26 15:01:09 UTC 
In the Linux kernel, the following vulnerability has been resolved:

net_sched: Flush gso_skb list too during ->change()

Previously, when reducing a qdisc's limit via the ->change() operation, only
the main skb queue was trimmed, potentially leaving packets in the gso_skb
list. This could result in NULL pointer dereference when we only check
sch->limit against sch->q.qlen.

This patch introduces a new helper, qdisc_dequeue_internal(), which ensures
both the gso_skb list and the main queue are properly flushed when trimming
excess packets. All relevant qdiscs (codel, fq, fq_codel, fq_pie, hhf, pie)
are updated to use this helper in their ->change() routines.
Comment 1 Avinash Hanwate 2025-05-26 15:11:46 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025052618-CVE-2025-37992-1590@gregkh/T