Bug 2536339 (CVE-2026-90387)

Summary: CVE-2026-90387 kernel: swiotlb: Preserve allocation virtual address for dynamic pools
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: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, 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 `swiotlb` component of the Linux kernel. When `CONFIG_DMA_DIRECT_REMAP` is enabled, the `swiotlb_init_io_tlb_pool()` function incorrectly reconstructs the virtual address for dynamic memory pools. This error causes `swiotlb_free_tlb()` to fail in recognizing allocated memory chunks, potentially leading to memory corruption or resource exhaustion. A local attacker could exploit this to impact system stability.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-09-17 17:28:17 UTC 
In the Linux kernel, the following vulnerability has been resolved:

swiotlb: Preserve allocation virtual address for dynamic pools

swiotlb_alloc_tlb() can allocate from the DMA atomic pool when a decrypted
pool is needed from atomic context. With CONFIG_DMA_DIRECT_REMAP, the
atomic pool is backed by remapped virtual addresses, which are not the same
as the direct-map addresses returned by phys_to_virt().

swiotlb_init_io_tlb_pool() currently reconstructs the pool virtual address
from the physical start address. For atomic-pool backed allocations this
stores the wrong address in pool->vaddr. Later, swiotlb_free_tlb() passes
that address to dma_free_from_pool(), which will fail to recognize the
chunk

Pass the virtual address returned by the allocation path into
swiotlb_init_io_tlb_pool(), and store that address in pool->vaddr. This
keeps the pool free path using the same virtual address as the allocator.
Comment 1 gkamathe 2026-09-21 07:36:34 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90387.mbox