Security update for the Linux Kernel (Live Patch 59 for SLE 15 SP3) SUSE Patch security@suse.de SUSE Security Team SUSE-SU-2025:02707-1 Final 1 1 2025-08-05T10:34:34Z current 2025-08-05T10:34:34Z 2025-08-05T10:34:34Z cve-database/bin/generate-cvrf.pl 2017-02-24T01:00:00Z Security update for the Linux Kernel (Live Patch 59 for SLE 15 SP3) This update for the Linux Kernel 5.3.18-150300_59_211 fixes one issue. The following security issue was fixed: - CVE-2025-37797: net_sched: hfsc: Fix a UAF vulnerability in class handling (bsc#1245793). The CVRF data is provided by SUSE under the Creative Commons License 4.0 with Attribution (CC-BY-4.0). SUSE-2025-2707,SUSE-SLE-Module-Live-Patching-15-SP3-2025-2707 Copyright SUSE LLC under the Creative Commons License 4.0 with Attribution (CC-BY-4.0) https://www.suse.com/support/update/announcement/2025/suse-su-202502707-1/ Link for SUSE-SU-2025:02707-1 https://lists.suse.com/pipermail/sle-updates/2025-August/041091.html E-Mail link for SUSE-SU-2025:02707-1 https://www.suse.com/support/security/rating/ SUSE Security Ratings https://bugzilla.suse.com/1245793 SUSE Bug 1245793 https://www.suse.com/security/cve/CVE-2025-37797/ SUSE CVE CVE-2025-37797 page SUSE Linux Enterprise Live Patching 15 SP3 kernel-livepatch-5_3_18-150300_59_211-default-2-150300.2.1 kernel-livepatch-5_3_18-150300_59_211-preempt-2-150300.2.1 kernel-livepatch-5_3_18-150300_59_211-default-2-150300.2.1 as a component of SUSE Linux Enterprise Live Patching 15 SP3 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. CVE-2025-37797 SUSE Linux Enterprise Live Patching 15 SP3:kernel-livepatch-5_3_18-150300_59_211-default-2-150300.2.1 important To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch". https://www.suse.com/support/update/announcement/2025/suse-su-202502707-1/ https://www.suse.com/security/cve/CVE-2025-37797.html CVE-2025-37797 https://bugzilla.suse.com/1242417 SUSE Bug 1242417 https://bugzilla.suse.com/1245793 SUSE Bug 1245793