CVE-2026-68204: media: vivid: check for vb2_is_busy() when toggling caps
In the Linux kernel, the following vulnerability has been resolved:
media: vivid: check for vb2isbusy() when toggling caps
The vividupdateformatcap/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 vividupdateformatcap/out will change the format, this can cause unexpected results.
Besides adding these checks, also add a WARNON in vividupdateformatcap/out() if the queue is busy.
I'm 90% certain that this is the cause of this syzbot bug:
https://syzkaller.appspot.com/bug?extid=dac8f5eaa46837e97b89
But since we never have reproducers, it is hard to be certain. In any case, these checks are needed regardless.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-68204?
The severity of CVE-2026-68204 is rated as risk 23.
How do I fix CVE-2026-68204?
To fix CVE-2026-68204, ensure that the vivid_update_format_cap/out() functions are called only when the capture/output queue is not busy.
What does CVE-2026-68204 affect?
CVE-2026-68204 affects the Linux kernel's media component, specifically the vivid driver.
Who is impacted by CVE-2026-68204?
Users of the Linux kernel that utilize the vivid driver for media handling may be impacted by CVE-2026-68204.
When was CVE-2026-68204 published?
CVE-2026-68204 was published on August 10, 2026.