7.8

CVE-2025-37890

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/
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Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Linux ≫ Linux Kernel Version >= 5.0.1 < 5.4.294
Linux ≫ Linux Kernel Version >= 5.5 < 5.10.238
Linux ≫ Linux Kernel Version >= 5.11 < 5.15.182
Linux ≫ Linux Kernel Version >= 5.16 < 6.1.138
Linux ≫ Linux Kernel Version >= 6.2 < 6.6.90
Linux ≫ Linux Kernel Version >= 6.7 < 6.12.28
Linux ≫ Linux Kernel Version >= 6.13 < 6.14.6
Linux ≫ Linux Kernel Version5.0 Update-
Linux ≫ Linux Kernel Version5.0 Updaterc3
Linux ≫ Linux Kernel Version5.0 Updaterc4
Linux ≫ Linux Kernel Version5.0 Updaterc5
Linux ≫ Linux Kernel Version5.0 Updaterc6
Linux ≫ Linux Kernel Version5.0 Updaterc7
Linux ≫ Linux Kernel Version5.0 Updaterc8
Linux ≫ Linux Kernel Version6.15 Updaterc1
Linux ≫ Linux Kernel Version6.15 Updaterc2
Linux ≫ Linux Kernel Version6.15 Updaterc3
Linux ≫ Linux Kernel Version6.15 Updaterc4
Debian ≫ Debian Linux Version11.0
Zu dieser CVE wurde keine CISA KEV oder CERT.AT-Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.02% 0.02
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
nvd@nist.gov 7.8 1.8 5.9
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE-416 Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.