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Linux Kernel: DVB DVR Device Reopen Bug Fix
published 7 months ago
Summary
A bug in the Linux kernel's DVB DVR device has been fixed, which could cause issues when reopening the device. This fix ensures that the device is properly reset when reopened, preventing data corruption and other problems. IT teams should review their kernel updates to ensure they have the latest version.
What to do
- Update linux kernel to version 6.19.7.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| Linux | linux | kernel |
>= 6.19.0, < 6.19.7 Fix: upgrade to 6.19.7
|
Original advisory text
media: dvb-core: fix wrong reinitialization of ringbuffer on reopen
In the Linux kernel, the following vulnerability has been resolved:
media: dvb-core: fix wrong reinitialization of ringbuffer on reopen
dvb_dvr_open() calls dvb_ringbuffer_init() when a new reader opens the
DVR device. dvb_ringbuffer_init() calls init_waitqueue_head(), which
reinitializes the waitqueue list head to empty.
Since dmxdev->dvr_buffer.queue is a shared waitqueue (all opens of the
same DVR device share it), this orphans any existing waitqueue entries
from io_uring poll or epoll, leaving them with stale prev/next pointers
while the list head is reset to {self, self}.
The waitqueue and spinlock in dvr_buffer are already properly
initialized once in dvb_dmxdev_init(). The open path only needs to
reset the buffer data pointer, size, and read/write positions.
Replace the dvb_ringbuffer_init() call in dvb_dvr_open() with direct
assignment of data/size and a call to dvb_ringbuffer_reset(), which
properly resets pread, pwrite, and error with correct memory ordering
without touching the waitqueue or spinlock.
media: dvb-core: fix wrong reinitialization of ringbuffer on reopen
dvb_dvr_open() calls dvb_ringbuffer_init() when a new reader opens the
DVR device. dvb_ringbuffer_init() calls init_waitqueue_head(), which
reinitializes the waitqueue list head to empty.
Since dmxdev->dvr_buffer.queue is a shared waitqueue (all opens of the
same DVR device share it), this orphans any existing waitqueue entries
from io_uring poll or epoll, leaving them with stale prev/next pointers
while the list head is reset to {self, self}.
The waitqueue and spinlock in dvr_buffer are already properly
initialized once in dvb_dmxdev_init(). The open path only needs to
reset the buffer data pointer, size, and read/write positions.
Replace the dvb_ringbuffer_init() call in dvb_dvr_open() with direct
assignment of data/size and a call to dvb_ringbuffer_reset(), which
properly resets pread, pwrite, and error with correct memory ordering
without touching the waitqueue or spinlock.
References
- https://git.kernel.org/stable/c/32eb8e4adc207ef31bc6e5ae56bab940b0176066 URL
- https://git.kernel.org/stable/c/af050ab44fa1b1897a940d7d756e512232f5e5df URL
- https://git.kernel.org/stable/c/bfbc0b5b32a8f28ce284add619bf226716a59bc0 URL
- https://git.kernel.org/stable/c/cfd94642025e6f71c8f754bdec0800ee95e4f3dd URL
- https://git.kernel.org/stable/c/d71781bad59b1c9d60d7068004581f9bf19c0c9d URL
- https://git.kernel.org/stable/c/f1e520ca2e83ece6731af6167c9e5e16931ecba0 URL
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23253... Vendor Advisory
- https://nvd.nist.gov/vuln/detail/CVE-2026-23253 Vendor Advisory
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git Product
Timeline
Published18 Mar 2026
Updated3 Jun 2026
First seen3 Jun 2026
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