Bug 2516589 (CVE-2026-72297)

Summary: CVE-2026-72297 kernel: net: atm: reject out-of-range traffic classes in QoS validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's Asynchronous Transfer Mode (ATM) networking module. This vulnerability occurs due to insufficient validation of traffic classes during Quality of Service (QoS) setup. A local user can exploit this by providing out-of-range traffic class values, which are then stored as invalid data. When the /proc/net/atm/pvc file is subsequently read, it leads to an out-of-bounds read, potentially resulting in information disclosure.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-08-15 06:20:32 UTC
In the Linux kernel, the following vulnerability has been resolved:

net: atm: reject out-of-range traffic classes in QoS validation

Reject ATM traffic classes above ATM_ANYCLASS in check_tp().
SO_ATMQOS stores the supplied QoS after check_qos() succeeds, so
accepting larger values leaves invalid traffic_class values in
vcc->qos.

That bad state later reaches pvc_info(), which indexes class_name[]
with vcc->qos.{rx,tp}.traffic_class. Values above ATM_ANYCLASS cause
an out-of-bounds read when /proc/net/atm/pvc is read.

Tighten the existing QoS validation so invalid traffic_class values
are rejected at the point where user supplied QoS is accepted.