In the Linux kernel, the following vulnerability has been resolved:
net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc
As described in Gerrard's report [1], we have a UAF case when an hfsc class
has a netem child qdisc. The crux of the issue is that hfsc is assuming
that checking for cl->qdisc->q.qlen == 0 guarantees that it hasn't inserted
the class in the vttree or eltree (which is not true for the netem
duplicate case).
This patch checks the n_active class variable to make sure that the code
won't insert the class in the vttree or eltree twice, catering for the
reentrant case.
[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
References
Configurations
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History
No history.
Information
Published : 2025-05-16 13:15
Updated : 2025-11-17 17:11
NVD link : CVE-2025-37890
Mitre link : CVE-2025-37890
CVE.ORG link : CVE-2025-37890
JSON object : View
Products Affected
debian
- debian_linux
linux
- linux_kernel
CWE
CWE-416
Use After Free
