Loop with Unreachable Exit Condition ('Infinite Loop') Affecting linux-virt-doc package, versions <6.12.22-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.03% (6th percentile)

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  • Snyk IDSNYK-MINIMOSLATEST-LINUXVIRTDOC-13806844
  • published2 Nov 2025
  • disclosed1 Apr 2025

Introduced: 1 Apr 2025

CVE-2025-21971  (opens in a new tab)
CWE-835  (opens in a new tab)

How to fix?

Upgrade Minimos:latest linux-virt-doc to version 6.12.22-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-virt-doc package and not the linux-virt-doc package as distributed by Minimos. See How to fix? for Minimos:latest relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

net_sched: Prevent creation of classes with TC_H_ROOT

The function qdisc_tree_reduce_backlog() uses TC_H_ROOT as a termination condition when traversing up the qdisc tree to update parent backlog counters. However, if a class is created with classid TC_H_ROOT, the traversal terminates prematurely at this class instead of reaching the actual root qdisc, causing parent statistics to be incorrectly maintained. In case of DRR, this could lead to a crash as reported by Mingi Cho.

Prevent the creation of any Qdisc class with classid TC_H_ROOT (0xFFFFFFFF) across all qdisc types, as suggested by Jamal.

CVSS Base Scores

version 3.1