In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_qfq: Fix null-deref in agg_dequeue
To prevent a potential crash in agg_dequeue (net/sched/sch_qfq.c)
when cl->qdisc->ops->peek(cl->qdisc) returns NULL, we check the return
value before using it, similar to the existing approach in sch_hfsc.c.
To avoid code duplication, the following changes are made:
1. Changed qdisc_warn_nonwc(include/net/pkt_sched.h) into a static
inline function.
2. Moved qdisc_peek_len from net/sched/sch_hfsc.c to
include/net/pkt_sched.h so that sch_qfq can reuse it.
3. Applied qdisc_peek_len in agg_dequeue to avoid crashing.
                
            Metrics
Affected Vendors & Products
References
        History
                    Thu, 30 Oct 2025 14:45:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| First Time appeared | Linux Linux linux Kernel | |
| Vendors & Products | Linux Linux linux Kernel | 
Thu, 30 Oct 2025 00:15:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| References |  | |
| Metrics | threat_severity 
 | cvssV3_1 
 
 | 
Wed, 29 Oct 2025 14:00:00 +0000
| Type | Values Removed | Values Added | 
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_qfq: Fix null-deref in agg_dequeue To prevent a potential crash in agg_dequeue (net/sched/sch_qfq.c) when cl->qdisc->ops->peek(cl->qdisc) returns NULL, we check the return value before using it, similar to the existing approach in sch_hfsc.c. To avoid code duplication, the following changes are made: 1. Changed qdisc_warn_nonwc(include/net/pkt_sched.h) into a static inline function. 2. Moved qdisc_peek_len from net/sched/sch_hfsc.c to include/net/pkt_sched.h so that sch_qfq can reuse it. 3. Applied qdisc_peek_len in agg_dequeue to avoid crashing. | |
| Title | net/sched: sch_qfq: Fix null-deref in agg_dequeue | |
| References |  | 
 MITRE
                        MITRE
                    Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-10-29T13:37:01.868Z
Reserved: 2025-04-16T07:20:57.161Z
Link: CVE-2025-40083
 Vulnrichment
                        Vulnrichment
                    No data.
 NVD
                        NVD
                    Status : Awaiting Analysis
Published: 2025-10-29T14:15:54.900
Modified: 2025-10-30T15:03:13.440
Link: CVE-2025-40083
 Redhat
                        Redhat