CVE-2026-74261 — ALSA: seq: avoid stale FIFO cells during resize

Affected: Linux

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

ALSA: seq: avoid stale FIFO cells during resize

snd_seq_fifo_resize() still needs to publish the replacement pool before it waits for FIFO users. A blocking snd_seq_read() holds f->use_lock while it sleeps, so concurrent senders must be able to queue to the new pool and wake that reader instead of failing against a closing old pool.

However, snd_seq_fifo_event_in() duplicates an event before it takes f->lock, and snd_seq_read() can dequeue a cell and later call snd_seq_fifo_cell_putback() if copy_to_user() or snd_seq_expand_var_event() fails. If resize swaps f->pool and detaches oldhead in between, either path can relink an old-pool cell after the snapshot. That stale cell sits outside the drained oldhead list, keeps oldpool->counter elevated, and can leave snd_seq_pool_delete() waiting for the retired pool to drain.

Keep the existing swap-before-wait ordering in snd_seq_fifo_resize(), but reject stale cells before any FIFO relink. Revalidate event-in cells under f->lock and retry them against the published replacement pool, and free stale putback cells instead of linking them back into the FIFO.

The buggy scenario involves two paths, with each column showing the order within that path:

resize path: relink path: 1. Allocate newpool. 1. Take f->use_lock. 2. Swap f->pool to newpool and 2. Duplicate or dequeue an old-pool detach oldhead. cell before old…

USN-8887-1 — linux, linux-aws, linux-gcp, linux-gke, linux-ibm, linux-oracle, linux-realtime vulnerabilities

Affected: Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-aws, Ubuntu:26.04:LTS: linux-gcp, Ubuntu:26.04:LTS: linux-gke, Ubuntu:26.04:LTS: linux-ibm, Ubuntu:26.04:LTS: linux-oracle, Ubuntu:26.04:LTS: linux-realtime

It was discovered that some AMD processors did not properly perform Reverse Map Table (RMP) checks when the IOMMU accessed certain host buffers. A local attacker with hypervisor access could possibly use this to trigger an out-of-bounds condition and compromise the integrity of SEV-SNP guest memory. (CVE-2023-20585)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - NVDIMM (Non-Volatile Memory Device) drivers; - Handshake API; - ARM32 architecture; - MIPS architecture; - OpenRISC architecture; - PowerPC architecture; - RISC-V architecture; - S390 architecture; - x86 architecture; - Cryptographic API; - Compute Acceleration Framework; - Intel NPU Driver; - ACPI drivers; - Android drivers; - Serial ATA and Parallel ATA drivers; - Drivers core; - Rados block device (RBD) driver; - Ublk userspace block driver; - Bluetooth drivers; - Cdrom driver; - Character device driver; - TPM device driver; - Data acquisition framework and drivers; - Hardware crypto device drivers; - CXL (Compute Express Link) drivers; - DAX dirext access to differentiated memory framework; - DIBS (Direct Internal Buffer Sharing) drivers; - Buffer Sharing and Synchronization framework; - DMA engine subsystem; - DPLL subsystem; - EDAC drivers; - FireWire subsystem; - Arm Firmware Framework fo…

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CVE-2026-74261 — ALSA: seq: avoid stale FIFO cells during resize

USN-8887-1 — linux, linux-aws, linux-gcp, linux-gke, linux-ibm, linux-oracle, linux-realtime vulnerabilities