SB20261022190 - Infinite loop in Linux kernel sched

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Main Vulnerability Database SB20261022190

SB20261022190 - Infinite loop in Linux kernel sched

Published: October 22, 2026

Security Bulletin ID SB20261022190
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Infinite loop (CVE-ID: CVE-2026-98610)

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to cause a denial of service by triggering an infinite packet-classification loop and a CPU soft lockup in the Linux kernel.

The vulnerability exists due to an infinite loop in hfsc_classify() in net/sched/sch_hfsc.c when class-level changes leave previously valid flowid bindings forming a cycle that bypasses the downward-level check. A local user can configure cyclic HFSC filter bindings and send a single packet through the affected queue to cause packet classification to loop indefinitely with the qdisc lock held and bottom halves disabled.

The required network configuration is reachable by an unprivileged user through unshare -Urn, which provides CAP_NET_ADMIN within the new user and network namespaces.


Remediation

Install update from vendor's website.

References