# CVE-2026-68176: tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev

CVE-2026-68176 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-68176, released August 11, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2026-68176
- Priority: Urgent
- CVSS: 9.8 (Critical)
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 10, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-68176

## Description

In the Linux kernel, the following vulnerability has been resolved:  tracing: Fix mmiotrace possible NULL dereferencing of hiter->dev  If the mmio_pipe_open() fails to find a PCI device, the hiter->dev will be assigned to NULL. The mmiotrace read() function dereferences the hiter->dev if hiter exists.  Change the test of the read to not only check hiter being NULL, but also the hiter->dev before dereferencing it.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 6.1.187-1 | [DEBIAN-CVE-2026-68176](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68176.md) | Aug 11, 2026 |
| Linux | linux Debian 13.5 (trixie) | 6.12.101-1 | [DEBIAN-CVE-2026-68176](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68176.md) | Aug 11, 2026 |
| Linux | linux Debian 14 | 7.1.6-1 | [DEBIAN-CVE-2026-68176](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68176.md) | Aug 11, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.101-1~deb12u1 | [DEBIAN-CVE-2026-68176](https://patchblox.com/security/data/fix/linux/debian-cve-2026-68176.md) | Aug 11, 2026 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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