cbcvebase.
CVE-2025-37797
published 2025-05-02

CVE-2025-37797: In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class handling This patch fixes a…

PriorityP339high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.18%
8.2th percentile
In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class handling This patch fixes a Use-After-Free vulnerability in the HFSC qdisc class handling. The issue occurs due to a time-of-check/time-of-use condition in hfsc_change_class() when working with certain child qdiscs like netem or codel. The vulnerability works as follows: 1. hfsc_change_class() checks if a class has packets (q.qlen != 0) 2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g., codel, netem) might drop packets and empty the queue 3. The code continues assuming the queue is still non-empty, adding the class to vttree 4. This breaks HFSC scheduler assumptions that only non-empty classes are in vttree 5. Later, when the class is destroyed, this can lead to a Use-After-Free The fix adds a second queue length check after qdisc_peek_len() to verify the queue wasn't emptied.

Affected

42 ranges· showing 25
VendorProductVersion rangeFixed in
debiandebian_linux
debianlinux< linux 6.1.137-1 (bookworm)linux 6.1.137-1 (bookworm)
debianlinux-6.1< linux 6.1.137-1 (bookworm)linux 6.1.137-1 (bookworm)
googlechrome_chrome
linuxlinux
linuxlinux>= 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 < 28b09a067831f7317c3841812276022d6c94067728b09a067831f7317c3841812276022d6c940677
linuxlinux>= 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 < 39b9095dd3b55d9b2743df038c32138efa34a9de39b9095dd3b55d9b2743df038c32138efa34a9de
linuxlinux>= 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 < fcc8ede663569c704fb00a702973bd6c00373283fcc8ede663569c704fb00a702973bd6c00373283
linuxlinux>= 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 < 20d584a33e480ae80d105f43e0e7b56784da41b920d584a33e480ae80d105f43e0e7b56784da41b9
linuxlinux>= 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 < 3aa852e3605000d5c47035c3fc3a986d14ccfa9f3aa852e3605000d5c47035c3fc3a986d14ccfa9f
linuxlinux>= 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 < 86cd4641c713455a4f1c8e54c370c598c2b1cee086cd4641c713455a4f1c8e54c370c598c2b1cee0
linuxlinux>= 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 < bb583c88d23b72d8d16453d24856c99bd93dadf5bb583c88d23b72d8d16453d24856c99bd93dadf5
linuxlinux>= 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 < 3df275ef0a6ae181e8428a6589ef5d5231e58b5c3df275ef0a6ae181e8428a6589ef5d5231e58b5c
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.237-15.10.237-1

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian7.8HIGH
vendor_redhat7.8HIGH
vendor_msrc7.0HIGH
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