CVE-2025-37890

Vulnerability overview

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 r...

Affected product and versions

Product

Linux Linux, linux kernel, debian linux

Affected versions

>= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 273bbcfa53541cde38b2003ad88a59b770306421, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < e0cf8ee23e1915431f262a7b2dee0c7a7d699af0, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < e3e949a39a91d1f829a4890e7dfe9417ac72e4d0, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 8df7d37d626430035b413b97cee18396b3450bef, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 6082a87af4c52f58150d40dec1716011d871ac21, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 2e7093c7a8aba5d4f8809f271488e5babe75e202, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < ac39fd4a757584d78ed062d4f6fd913f83bd98b5, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 141d34391abbb315d68556b7c67ad97885407547, >= 5.0, >= 5.0.1 < 5.4.294, >= 5.5 < 5.10.238, >= 5.11 < 5.15.182, >= 5.16 < 6.1.138, >= 6.2 < 6.6.90, >= 6.7 < 6.12.28, >= 6.13 < 6.14.6, 5.0, 6.15, 11.0

Fixed versions

5.4.294, 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28, 6.14.6

Technical data

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE

CWE-416