CVE Catalog

CVE-2025-37915

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.17%

7th percentile - higher than 7% of all known CVEs

Summary

In the Linux kernel's DRR (Deficit Round Robin) network scheduler, a vulnerability was found causing a double addition of a class to the active list when a netem child qdisc causes reentrant enqueue in the parent. This leads to memory corruption. The fix adds a check whether the class is already on the active list before adding.

Risk Assessment

The organization is at risk of memory corruption and potential system crashes when using DRR queuing with netem as a child qdisc, which could disrupt network operations.

Recommendation

Update the Linux kernel to a version containing the fix that adds a cl_is_active check before adding the class to the active list.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net_sched: drr: 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 drr, 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 adding to the list to cover for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/

Vulnerability data from NVD (NIST) · CISA KEV · EPSS