CVE-2025-38477 net/sched: sch_qfq: Fix race condition on qfq_aggregate
A race condition in the Linux kernel's QFQ scheduler allows attackers to trigger use-after-free or NULL dereference, potentially causing crashes or code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38477?
CVE-2025-38477 is a high-severity vulnerability in Debian Debian Linux, published on 28 Jul 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_qfq: Fix race condition on qfq_aggregate
A race condition can occur when 'agg' is modified in qfq_change_agg (called during qfq_enqueue) while other threads access it concurrently. For example, qfq_dump_class may trigger a NULL dereference, and qfq_delete_class may cause a use-after-free.
This patch addresses the issue by:
1. Moved qfq_destroy_class into the critical section.
2. Added sch_tree_lock protection to qfq_dump_class and qfq_dump_class_stats.
Weakness: CWE-362
Which versions are affected by CVE-2025-38477?
It affects 2 products.
Linux distribution packages (14)
kgraft-patch-SLE12-SP5_Update_69 SUSE:Linux Enterprise Live Patching 12 SP5 | All versions | 5-2.1 |
kgraft-patch-SLE12-SP5_Update_70 SUSE:Linux Enterprise Live Patching 12 SP5 | All versions | 5-2.1 |
kernel-livepatch-SLE15-SP3_Update_58 SUSE:Linux Enterprise Live Patching 15 SP3 | All versions | 6-150300.2.1 |
kernel-livepatch-SLE15-SP4_Update_41 SUSE:Linux Enterprise Live Patching 15 SP4 | All versions | 6-150400.2.1 |
kernel-livepatch-SLE15-SP4_Update_42 SUSE:Linux Enterprise Live Patching 15 SP4 | All versions | 5-150400.2.1 |
kernel-livepatch-SLE15-SP5_Update_29 SUSE:Linux Enterprise Live Patching 15 SP5 | All versions | 4-150500.2.1 |
kernel-livepatch-SLE15-SP6-RT_Update_13 SUSE:Linux Enterprise Live Patching 15 SP6 | All versions | 5-150600.2.1 |
kernel-livepatch-SLE15-SP6_Update_13 SUSE:Linux Enterprise Live Patching 15 SP6 | All versions | 5-150600.2.1 |
kernel-livepatch-SLE15-SP7-RT_Update_2 SUSE:Linux Enterprise Live Patching 15 SP7 | All versions | 5-150700.2.1 |
kernel-livepatch-SLE15-SP7_Update_2 SUSE:Linux Enterprise Live Patching 15 SP7 | All versions | 5-150700.2.1 |
kernel-livepatch-MICRO-6-0-RT_Update_10 SUSE:Linux Micro 6.0 | All versions | 5-1.1 |
kernel-livepatch-MICRO-6-0_Update_9 SUSE:Linux Micro 6.0 | All versions | 6-1.2 |
kernel-livepatch-MICRO-6-0-RT_Update_10 SUSE:Linux Micro 6.1 | All versions | 5-1.1 |
kernel-livepatch-MICRO-6-0_Update_9 SUSE:Linux Micro 6.1 | All versions | 6-1.2 |
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-38477?
Apply the vendor's patch.
Is CVE-2025-38477 being exploited?
There is no known exploitation of CVE-2025-38477 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as AZL-65907, AZL-73046, BELL-CVE-2025-38477, DEBIAN-CVE-2025-38477, GHSA-79vc-v8qm-8x53, OESA-2025-2057 and 19 more.