CVE-2025-38595 Information

Aug 20, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

xen: fix UAF in dmabuf_exp_from_pages()

[dma_buf_fd() fixes; no preferences regarding the tree it goes through - up to xen folks]

As soon as we’d inserted a file reference into descriptor table another thread could close it. That’s fine for the case when all we are doing is returning that descriptor to userland (it’s a race but it’s a userland race and there’s nothing the kernel can do about it). However if we follow fd_install() with any kind of access to objects that would be destroyed on close (be it the struct file itself or anything destroyed by its ->release()) we have a UAF.

dma_buf_fd() is a combination of reserving a descriptor and fd_install(). gntdev dmabuf_exp_from_pages() calls it and then proceeds to access the objects destroyed on close - starting with gntdev_dmabuf itself.

Fix that by doing reserving descriptor before anything else and do fd_install() only when everything had been set up.

Reference

https://git.kernel.org/stable/c/3edfd2353f301bfffd5ee41066e37320a59ccc2d https://git.kernel.org/stable/c/532c8b51b3a8676cbf533a291f8156774f30ea87 https://git.kernel.org/stable/c/d59d49af4aeed9a81e673e37c26c6a3bacf1a181 https://git.kernel.org/stable/c/e5907885260401bba300d4d18d79875c05b82651

CNNVD-202508-2159 (Published: 2025-08-19)

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