# CVE-2026-53373: linux: In the Linux kernel, the following vulnerability has been resolved:  mm/vma: do not try to unmap a VMA if mmap_prepar...

CVE-2026-53373 is fixed in linux on 1 platform by DEBIAN-CVE-2026-53373 (version 7.0.9-1), released July 20, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-53373
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 19, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  mm/vma: do not try to unmap a VMA if mmap_prepare() invoked from mmap()  The mmap_prepare hook functionality includes the ability to invoke mmap_prepare() from the mmap() hook of existing 'stacked' drivers, that is ones which are capable of calling the mmap hooks of other drivers/file systems (e.g.  overlayfs, shm).  As part of the mmap_prepare action functionality, we deal with errors by unmapping the VMA should one arise.  This works in the usual mmap_prepare case, as we invoke this action at the last moment, when the VMA is established in the maple tree.  However, the mmap() hook passes a not-fully-established VMA pointer to the caller (which is the motivation behind the mmap_prepare() work), which is detached.  So attempting to unmap a VMA in this state will be problematic, with the most obvious symptom being a warning in vma_mark_detached(), because the VMA is already detached.  It's also unncessary - the mmap() handler will clean up the VMA on error.  So to fix this issue, this patch propagates whether or not an mmap action is being completed via the compatibility layer or directly.  If the former, then we do not attempt VMA cleanup, if the latter, then we do.  This patch also updates the userland VMA tests to reflect the change.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 7.0.9-1 | [DEBIAN-CVE-2026-53373](https://patchblox.com/security/data/fix/linux/debian-cve-2026-53373.md) | Jul 20, 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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