Bug 2387588 (CVE-2025-8860)

Summary: CVE-2025-8860 qemu-kvm: uefi-vars: information disclosure vulnerability in uefi_vars_write callback
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: ailan, ddepaula, jen, jferlan, jmaloy, kkiwi, knoel, mrezanin, mst, nilal, pbonzini, ymankad
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in QEMU in the uefi-vars virtual device. When the guest writes to register UEFI_VARS_REG_BUFFER_SIZE, the .write callback `uefi_vars_write` is invoked. The function allocates a heap buffer without zeroing the memory, leaving the buffer filled with residual data from prior allocations. When the guest later reads from register UEFI_VARS_REG_PIO_BUFFER_TRANSFER, the .read callback `uefi_vars_read` returns leftover metadata or other sensitive process memory from the previously allocated buffer, leading to an information disclosure vulnerability.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2387590    
Bug Blocks:    

Description OSIDB Bzimport 2025-08-11 10:39:35 UTC
When the guest writes to register UEFI_VARS_REG_BUFFER_SIZE, the .write
callback `uefi_vars_write` is invoked. The function allocates a
heap buffer without zeroing the memory, leaving the buffer filled with
residual data from prior allocations. When the guest later reads from
register UEFI_VARS_REG_PIO_BUFFER_TRANSFER, the .read callback
`uefi_vars_read` returns leftover metadata or other sensitive process
memory from the previously allocated buffer, leading to an information
disclosure vulnerability.