Bug 2448685 (CVE-2026-23253) - CVE-2026-23253 kernel: Kernel: Denial of Service via DVB DVR ringbuffer reinitialization flaw
Summary: CVE-2026-23253 kernel: Kernel: Denial of Service via DVB DVR ringbuffer reini...
Keywords:
Status: NEW
Alias: CVE-2026-23253
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-03-18 18:02 UTC by OSIDB Bzimport
Modified: 2026-03-24 19:42 UTC (History)
0 users

Fixed In Version:
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Description OSIDB Bzimport 2026-03-18 18:02:17 UTC
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.


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