# CVE-2026-46017: mm: fix deferred split queue races during migration

CVE-2026-46017 is fixed in linux on 1 platform by DEBIAN-CVE-2026-46017 (version 7.0.4-1), released May 27, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-46017
- Priority: High
- CVSS: 7.0 (Moderate)
- EPSS: 0.0011
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 27, 2026
- Weakness: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-46017

## Description

In the Linux kernel, the following vulnerability has been resolved:  mm: fix deferred split queue races during migration  migrate_folio_move() records the deferred split queue state from src and replays it on dst.  Replaying it after remove_migration_ptes(src, dst, 0) makes dst visible before it is requeued, so a concurrent rmap-removal path can mark dst partially mapped and trip the WARN in deferred_split_folio().  Move the requeue before remove_migration_ptes() so dst is back on the deferred split queue before it becomes visible again.  Because migration still holds dst locked at that point, teach deferred_split_scan() to requeue a folio when folio_trylock() fails.  Otherwise a fully mapped underused folio can be dequeued by the shrinker and silently lost from split_queue.  [ziy@nvidia.com: move the comment]

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.0.4-1 | [DEBIAN-CVE-2026-46017](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46017.md) | May 27, 2026 |

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Data as of 2026-11-08T06:59:42Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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