Medium [CVE-2026-68176] Null pointer dereference in mmiotrace can lead to denial of service
This medium-severity Red Hat Linux advisory covers CVE-2026-68176 affecting Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8.
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Summary
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. The `mmiotrace read()` function then attempts to dereference this null pointer, which can lead to a system crash and result in a denial of service.
A local attacker could potentially exploit this to cause system instability. Red Hat severity: Moderate — CVSS 4.4 (CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-476. Affected Red Hat products: Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9; Red Hat OpenShift Container Platform 4.
Red Hat lists Red Hat Enterprise Linux 10; Red Hat Enterprise Linux for NVIDIA 26 as not affected. Will not fix / out of support: Red Hat Enterprise Linux 6.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: kernel-rt.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 1 hour ago·verify at source
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