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
Configuration 1 (hide)
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Configuration 2 (hide)
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History
17 Nov 2025, 17:11
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-416 | |
| First Time |
Linux linux Kernel
Debian Debian debian Linux Linux |
|
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
| CPE | cpe:2.3:o:linux:linux_kernel:5.0:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.0:rc4:*:*:*:*:*:* cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.0:rc7:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.0:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.0:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.0:-:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:5.0:rc8:*:*:*:*:*:* |
|
| References | () https://git.kernel.org/stable/c/141d34391abbb315d68556b7c67ad97885407547 - Patch | |
| References | () https://git.kernel.org/stable/c/273bbcfa53541cde38b2003ad88a59b770306421 - Patch | |
| References | () https://git.kernel.org/stable/c/2e7093c7a8aba5d4f8809f271488e5babe75e202 - Patch | |
| References | () https://git.kernel.org/stable/c/6082a87af4c52f58150d40dec1716011d871ac21 - Patch | |
| References | () https://git.kernel.org/stable/c/8df7d37d626430035b413b97cee18396b3450bef - Patch | |
| References | () https://git.kernel.org/stable/c/ac39fd4a757584d78ed062d4f6fd913f83bd98b5 - Patch | |
| References | () https://git.kernel.org/stable/c/e0cf8ee23e1915431f262a7b2dee0c7a7d699af0 - Patch | |
| References | () https://git.kernel.org/stable/c/e3e949a39a91d1f829a4890e7dfe9417ac72e4d0 - Patch | |
| References | () https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html - Mailing List | |
| References | () https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html - Mailing List |
03 Nov 2025, 20:18
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
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
linux
- linux_kernel
debian
- debian_linux
CWE
CWE-416
Use After Free
