CVE-2026-63910

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

dma-buf: fix UAF in dma_buf_fd() tracepoint

Once FD_ADD() returns, the fd is live in the file descriptor table

and a thread sharing that table can close() it before DMA_BUF_TRACE()

runs. The close drops the last reference, __fput() frees the dma_buf,

and the tracepoint then dereferences dmabuf to take dmabuf->name_lock

-- slab-use-after-free.

Split FD_ADD() back into get_unused_fd_flags() + fd_install() and

emit the tracepoint between them. While the fdtable slot is reserved

with a NULL file pointer, a racing close() returns -EBADF without

entering __fput(), so the dma_buf stays alive across the trace. Same

approach as commit 2d76319c4cbb ("dma-buf: fix UAF in dma_buf_put()

tracepoint").

This undoes the FD_ADD() conversion done in commit 34dfce523c90

("dma: convert dma_buf_fd() to FD_ADD()"); FD_ADD() has no place to

hook the tracepoint safely.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References