Executive brief
A race condition exists in the Linux kernel's parallel port (parport) subsystem that can cause a system crash during boot or when loading hardware drivers. This occurs because the system attempts to connect printer or other parallel port drivers before the underlying hardware interface is fully ready. While primarily affecting older hardware or specific virtualized environments, an exploit could lead to a denial-of-service by destabilizing the operating system.
Technical details
A race condition exists in the Linux kernel parport subsystem due to port devices being registered via device_add() before full initialization is complete. This allows client drivers (such as 'lp') to attempt attachment to ports that are not yet ready or are in the process of being removed. The vulnerability is most prominent when port and client drivers are loaded as modules simultaneously, leading to a null pointer dereference or similar memory corruption resulting in a kernel panic. The fix introduces a PARPORT_ANNOUNCED flag to ensure client drivers only attach to ports that have completed the announcement phase.
Affected products
- Linux Linux 6fa45a226897 to f3378b0d7bd4
Timeline
- 2026-05-05: other: Patch authored
- 2026-06-19: patched: Patch committed to stable tree
- 2026-07-19: disclosed: CVE published
References
- https://git.kernel.org/stable/c/15b1723c1472e802f9f7e69ae4e64f7dbf588848
- https://git.kernel.org/stable/c/290f515c5e3b3900bc2fe24f179999fd08d23bfa
- https://git.kernel.org/stable/c/51026cff1f4f3b762a0b5a07c727bd59cef45320
- https://git.kernel.org/stable/c/74d6aae1df45d3414178986be743f946988fddf6
- https://git.kernel.org/stable/c/a1e81b58da0179531bedf0b9f2811f5f992d5c4b
- https://git.kernel.org/stable/c/d16548be2ea5058227d79799e81dab61c9bca8ec
- https://git.kernel.org/stable/c/ef15ccbb3e8640a723c42ad90eaf81d66ae02017