Bug 2493704 (CVE-2026-53278)

Summary: CVE-2026-53278 kernel: arm_mpam: Check whether the config array is allocated before destroying it
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's arm_mpam component. This vulnerability occurs when the `__destroy_component_cfg()` function is called from `mpam_disable()` before the configuration array has been properly allocated. This can lead to a null pointer dereference, potentially causing a system crash and resulting in a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-06-26 21:01:47 UTC 
In the Linux kernel, the following vulnerability has been resolved:

arm_mpam: Check whether the config array is allocated before destroying it

__destroy_component_cfg() is called to free the configuration array.
It uses the embedded 'garbage' structure, which means the array has
to be allocated.

If __destroy_component_cfg() is called from mpam_disable() before the
configuration was ever allocated, then a NULL pointer is dereferenced.

Check for this case and return early if the configuration is not
allocated.

__destroy_component_cfg() also frees the mbwu_state as this is allocated
by __allocate_component_cfg(). As the mbwu_state is allocated after
comp->cfg is set, and is also under mpam_list_lock, only the first
pointer needs checking.
Comment 1 Mauro Matteo Cascella 2026-06-29 10:52:08 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062611-CVE-2026-53278-ec2a@gregkh/T