# CVE-2026-31735: linux: In the Linux kernel, the following vulnerability has been resolved:  iommupt: Fix short gather if the unmap goes into...

CVE-2026-31735 is fixed in linux on 1 platform by DEBIAN-CVE-2026-31735 (version 6.19.12-1), released May 15, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-31735
- Priority: High
- CVSS: 8.8 (high)
- EPSS: 0.0012
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 1, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  iommupt: Fix short gather if the unmap goes into a large mapping  unmap has the odd behavior that it can unmap more than requested if the ending point lands within the middle of a large or contiguous IOPTE.  In this case the gather should flush everything unmapped which can be larger than what was requested to be unmapped. The gather was only flushing the range requested to be unmapped, not extending to the extra range, resulting in a short invalidation if the caller hits this special condition.  This was found by the new invalidation/gather test I am adding in preparation for ARMv8. Claude deduced the root cause.  As far as I remember nothing relies on unmapping a large entry, so this is likely not a triggerable bug.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.19.12-1 | [DEBIAN-CVE-2026-31735](https://patchblox.com/security/data/fix/linux/debian-cve-2026-31735.md) | May 15, 2026 |

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Data as of 2026-11-08T19:12:23Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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