Medium [CVE-2026-68204] Linux kernel: System instability due to improper video format handling in vivid driver
This medium-severity Red Hat Linux advisory covers CVE-2026-68204 affecting Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4.
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Summary
In the Linux kernel, the following vulnerability has been resolved: media: vivid: check for vb2_is_busy() when toggling caps The vivid_update_format_cap/out() functions must only be called if the capture/output queue are not busy. But for the controls that select the CROP/COMPOSE/SCALE capability that is not checked.
Only when streaming starts will they be set to 'grabbed' and it is impossible to change the control, but between REQBUFS and STREAMON you are still allowed to set these controls. Since vivid_update_format_cap/out will change the format, this can cause unexpected results.
Besides adding these checks, also add a WARN_ON in vivid_update_format_cap/out() if the queue is busy. I'm 90% certain that this is the cause of this syzbot bug: But since we never have reproducers, it is hard to be certain.
In any case, these checks are needed regardless. A flaw was found in the Linux kernel's media subsystem, specifically within the vivid driver.
The vivid_update_format_cap/out() functions, which handle video format changes, can be called when the video buffer queue is actively processing data. This occurs because checks for a busy queue are missing when certain capabilities are toggled between the buffer request and streaming start phases.
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 2 hours 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 2 hours 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 2 hours ago·verify at source
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