CVE-2025-37890

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Source
https://cve.org/CVERecord?id=CVE-2025-37890
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-37890.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2025-37890
Downstream
Related
Published
2025-05-16T13:01:12.798Z
Modified
2026-05-28T03:54:49.259074367Z
Summary
net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc
Details

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/

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37890.json",
    "cna_assigner": "Linux"
}
References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type
GIT
Repo
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events
Introduced
37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea
Fixed
273bbcfa53541cde38b2003ad88a59b770306421
Fixed
e0cf8ee23e1915431f262a7b2dee0c7a7d699af0
Fixed
e3e949a39a91d1f829a4890e7dfe9417ac72e4d0
Fixed
8df7d37d626430035b413b97cee18396b3450bef
Fixed
6082a87af4c52f58150d40dec1716011d871ac21
Fixed
2e7093c7a8aba5d4f8809f271488e5babe75e202
Fixed
ac39fd4a757584d78ed062d4f6fd913f83bd98b5
Fixed
141d34391abbb315d68556b7c67ad97885407547

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-37890.json"

Linux / Kernel

Package

Name
Kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
5.0.0
Fixed
5.4.294
Type
ECOSYSTEM
Events
Introduced
5.5.0
Fixed
5.10.238
Type
ECOSYSTEM
Events
Introduced
5.11.0
Fixed
5.15.182
Type
ECOSYSTEM
Events
Introduced
5.16.0
Fixed
6.1.138
Type
ECOSYSTEM
Events
Introduced
6.2.0
Fixed
6.6.90
Type
ECOSYSTEM
Events
Introduced
6.7.0
Fixed
6.12.28
Type
ECOSYSTEM
Events
Introduced
6.13.0
Fixed
6.14.6

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-37890.json"