CVE-2025-37890
Description
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/
How to fix
- linux linux_kernel5.4.294, 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28, 6.14.6 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| linux linux_kernel | 5.0.1 ≤ v < 5.4.294, 5.5 ≤ v < 5.10.238, 5.11 ≤ v < 5.15.182, 5.16 ≤ v < 6.1.138, 6.2 ≤ v < 6.6.90, 6.7 ≤ v < 6.12.28, 6.13 ≤ v < 6.14.6, 5.0, 6.15 | 5.4.294, 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28, 6.14.6 |
| debian debian_linux | 11.0 | — |
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