# CVE-2026-89804: linux: In the Linux kernel, the following vulnerability has been resolved:  drm/nouveau/dmem: fix mismatched DMA unmap size...

CVE-2026-89804 is fixed in linux on 1 platform by DEBIAN-CVE-2026-89804 (version 7.2.6-1), released September 23, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-89804
- Priority: High
- CVSS: 8.8 (high)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 16, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  drm/nouveau/dmem: fix mismatched DMA unmap size for large folios  Device-private THP migration maps migration buffers with page_size() and records that length in dma_info->size.  For a compound folio page_size() is PAGE_SIZE << order, but two teardown sites still pass a literal PAGE_SIZE to dma_unmap_page():    - nouveau_dmem_migrate_to_ram() on the success path, and   - nouveau_dmem_migrate_copy_one() on the copy-error path.  For an order > 0 folio this unmaps less than was mapped, leaking the remainder of the IOMMU/IOVA mapping.  The other unmap sites, in nouveau_dmem_migrate_chunk() and nouveau_dmem_evict_chunk(), already use the saved size; use it here too.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89804](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89804.md) | Sep 23, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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