CVE-2025-37914 net_sched: ets: Fix double list add in class with netem as child qdisc
A double list addition in the Linux kernel ETS scheduler with netem child qdiscs causes memory corruption, potentially leading to code execution or denial of service.
- 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-2025-37914?
CVE-2025-37914 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 20 May 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: ets: Fix double list add in class with netem as child qdisc
As described in Gerrard's report [1], there are use cases where a netem child qdisc will make the parent qdisc's enqueue callback reentrant. In the case of ets, there won't be a UAF, but the code will add the same classifier to the list twice, which will cause memory corruption.
In addition to checking for qlen being zero, this patch checks whether the class was already added to the active_list (cl_is_active) before doing the addition to cater for the reentrant case.
[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
Weakness: CWE-415
Which versions are affected by CVE-2025-37914?
It affects 2 products.
Products include Debian Debian Linux, Linux kernel.
How do I fix CVE-2025-37914?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-37914 being exploited?
There is no known exploitation of CVE-2025-37914 in the wild and no public exploit code.
Other vulnerabilities in Debian Debian Linux
Sources
Also known as BELL-CVE-2025-37914, DEBIAN-CVE-2025-37914, GHSA-x88q-4f25-f826, ROOT-OS-DEBIAN-11-CVE-2025-37914, ROOT-OS-DEBIAN-12-CVE-2025-37914, ROOT-OS-UBUNTU-2204-CVE-2025-37914 and 2 more.