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 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.
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:4.14:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:4.14:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:4.14:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:4.14:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:4.14:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:4.14:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:4.14:rc7:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:4.14:rc8:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*

Configuration 2 (hide)

cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

History

No history.

Information

Published : 2025-05-02 15:15

Updated : 2025-11-06 20:48


NVD link : CVE-2025-37797

Mitre link : CVE-2025-37797

CVE.ORG link : CVE-2025-37797


JSON object : View

Products Affected

debian

  • debian_linux

linux

  • linux_kernel
CWE
CWE-416

Use After Free