CVE-2026-68204
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
In the Linux kernel, in the vivid driver, there is a missing check for vb2_is_busy() when toggling capabilities. The vivid_update_format_cap/out() functions can be called when the capture/output queue is not busy, but for controls that select CROP/COMPOSE/SCALE capability, this check is not performed. This can lead to unexpected results when the format is changed between REQBUFS and STREAMON.
Risk Assessment
This can cause unpredictable driver behavior, including potential crashes or incorrect operation when the user changes controls at an inappropriate time.
Recommendation
Apply the Linux kernel patch that adds vb2_is_busy() checks and WARN_ON in vivid_update_format_cap/out() to prevent format changes when the queue is busy.
Original NVD description (English source)
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: 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.