CVE-2026-89996
UnknownSummary
In the Linux kernel dma-heap interface (DMA_HEAP_IOCTL_ALLOC), the dma-buf file descriptor was published into the caller's fd table before the result was copied back to userspace. If the trailing copy_to_user() failed, the fd remained visible to other threads and leaked for the lifetime of the process. The fix restructures the allocation path so that fd installation is the last, unfailable step.
Risk Assessment
A local user can repeatedly trigger the vulnerable ioctl (e.g. by flipping a page's protection to PROT_READ between copy_from_user() and copy_to_user()), leaking dma-buf file descriptors and exhausting process or system resources. This can lead to denial of service (DoS) and uncontrolled memory consumption via dma-buf handles.
Recommendation
Update the Linux kernel to a version containing the fix that introduces the dma_buf_fd_install() helper and reorders operations in dma_heap_ioctl_allocate(). If updating is not possible, restrict access to /dev/dma_heap/* devices to trusted processes only.
Other vulnerabilities in Linux kernel
See all- CVE-2026-98163Unknown
A vulnerability was found in the Linux kernel's cgroup subsystem, involving iteration over dying tasks with a zero reference count. This leads to a race condition where the iterator may access a task after it has been freed, resulting in a use-after-free.
- CVE-2026-98162Unknown
In the Linux kernel, the smb2_tree_connect() function of the SMB server (ksmbd) leaks a tree connection. When ksmbd_iov_pin_rsp() fails, the newly created tree connection is not disconnected, leading to a resource leak.
- CVE-2026-98161Unknown
In the Linux kernel, the nvdimm (pmem) pmem_submit_bio() function records a REQ_PREFLUSH error but continues to copy bio data and can later overwrite the error with a successful REQ_FUA flush. This allows data writes to run after a failed preflush and can complete the bio successfully despite the failed ordering barrier.
- CVE-2026-98160Unknown
In the Linux kernel, the staging rtl8723bs driver's rtw_sdio_if1_init() function frees padapter->HalData with kfree(), even though it was allocated via vzalloc(). Using kfree() to release a vmalloc-backed buffer can lead to memory corruption.
- CVE-2026-100079Unknown
In the Linux kernel, the USB Type-C (ucsi) subsystem's ucsi_register() creates per-instance debugfs entries, but ucsi_unregister() keeps them until ucsi_destroy(). Drivers like ucsi_glink that unregister/register the same UCSI instance across remoteproc restart then try to create an already existing debugfs directory.
- CVE-2026-100078Unknown
In the Linux kernel, the iwlwifi (mei) driver's iwl_mei_write_cyclic_buf() function receives an incorrect first argument — the q_head pointer is passed instead of cldev. The bug has been fixed.
- CVE-2026-100077Unknown
In the Linux kernel, the drm/msm driver does not safely retire a hung submit before GPU recovery completes. Retiring the submit triggers BO free, which can result in GPU pagefaults since the GPU may be actively accessing those BOs.
- CVE-2026-100074Unknown
In the Linux kernel, a bug was fixed where the BPF_REFCOUNT field was not marked as unique, although it should be. The fix addresses this oversight.
- CVE-2026-100073Unknown
In the Linux kernel, a bug in the ext4 filesystem related to transaction overflow during writeback was fixed. A previous fix was too eager in reducing reserved transaction credits, leading to insufficient reservation in some corner cases. The fix uses ext4_meta_trans_blocks() for a correct upper bound estimate.
- CVE-2026-100072Unknown
In the Linux kernel, a problem in the ACPI subsystem was fixed where the use of acpi_get_first_physical_node() in acpi_platform_fill_resource() and acpi_create_platform_device() was unsafe because the returned device could be freed at any time. The fix replaces it with acpi_bus_get_primary_device() and adjusts the code to call it only once.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: dma-buf: dma-heap: don't publish fd before copy_to_user() succeeds DMA_HEAP_IOCTL_ALLOC allocates a dma-buf and installs an fd into the caller's fd table via dma_buf_fd() -> fd_install() before dma_heap_ioctl() copies the result back to userspace. If the trailing copy_to_user() fails, userspace never learns the fd number, but the fd (and the underlying dma-buf reference) are already visible to other threads in the same process and are leaked for the lifetime of the process. The obvious "close it on the failure path" fix is unsafe: once fd_install() has run, another thread can already dup() the fd, send it via SCM_RIGHTS, or close() it and let its number be reused, so a subsequent close_fd() from the ioctl path can operate on an unrelated file. This was pointed out by Christian König on v1 [1]. Restructure the allocation path so that fd_install() is the last, unfailable step of a successful ioctl: 1. heap->ops->allocate() creates the dma_buf. 2. get_unused_fd_flags() reserves an fd number in the caller's fd table without publishing it, so no other thread can observe it. 3. copy_to_user() delivers the fd number to userspace; on failure the fd is returned with put_unused_fd() and the dma_buf reference is dropped with dma_buf_put(), leaving no user- visible state behind. 4. dma_buf_fd_install() publishes the fd and emits the trace_dma_buf_fd tracepoint -- from here on the ioctl cannot fail. A new dma_buf_fd_install() helper is introduced in dma-buf.c to wrap fd_install() together with the DMA_BUF_TRACE() call, preserving the export tracing that dma_buf_fd() provides. dma_heap_ioctl_allocate() is refactored to return the struct dma_buf * directly (returning ERR_PTR on failure) so the caller holds the dmabuf reference across steps 3 and 4. The failure at step 3 is easily reachable from userspace: pass a struct dma_heap_allocation_data that lives in a page whose protection is flipped to PROT_READ between copy_from_user() and copy_to_user() (e.g. via mprotect()). Before this change each such ioctl leaks one dmabuf fd; after it, the fd table is unchanged on failure and only /dev/dma_heap/<name> remains open. No UAPI or heap-driver interface change. [1] https://lore.kernel.org/dri-devel/[email protected]/
Vulnerability data from NVD (NIST) · CISA KEV · EPSS