CVE-2026-64264 — fuse-uring: fix EFAULT clobber in fuse_uring_commit

Affected: Linux

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

fuse-uring: fix EFAULT clobber in fuse_uring_commit

copy_from_user() returns the number of bytes not copied as an unsigned residual on failure (1..sizeof(struct fuse_out_header)). fuse_uring_commit stores that residual in ssize_t err, sets req->out.h.error to -EFAULT, then jumps to out: with err still holding the positive residual.

err = copy_from_user(&req->out.h, &ent->headers->in_out, sizeof(req->out.h)); if (err) { req->out.h.error = -EFAULT; goto out; /* err is the positive residual */ } ... out: fuse_uring_req_end(ent, req, err);

fuse_uring_req_end() then runs

if (error) req->out.h.error = error;

which overwrites the just-assigned -EFAULT with the positive residual. FUSE callers such as fuse_simple_request() test err < 0 to detect failure, so the positive value is interpreted as success and the caller proceeds with an uninitialised or partial req->out.args.

Fix by assigning err = -EFAULT in the failure branch before jumping to out, so fuse_uring_req_end() receives a negative errno and sets req->out.h.error to -EFAULT.

USN-8726-1 — linux, linux-aws, linux-aws-7.0, linux-gcp, linux-gke, linux-hwe-7.0, linux-realtime vulnerabilities

Affected: Ubuntu:24.04:LTS: linux-aws-7.0, Ubuntu:24.04:LTS: linux-hwe-7.0, 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-realtime

It was discovered that some Arm processors could complete a broadcast translation lookaside buffer (TLB) invalidation before memory writes made through the invalidated translation were globally observed. A local attacker could possibly use this to write to memory after permission to do so had been revoked, bypassing memory protections or escalating privileges. (CVE-2025-10263)

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; - User-space API (UAPI); - Kernel build system; - ARM32 architecture; - RISC-V architecture; - S390 architecture; - x86 architecture; - Block layer subsystem; - Cryptographic API; - Compute Acceleration Framework; - Intel NPU Driver; - ACPI drivers; - Android drivers; - Drivers core; - Compressed RAM block device driver; - Bluetooth drivers; - Character device driver; - Hardware random number generator core; - CPU frequency scaling framework; - Hardware crypto device drivers; - Buffer Sharing and Synchronization framework; - Intel Stratix 10 firmware drivers; - FPGA Framework; - GPIO subsystem; - GPU drivers; - HID subsystem; - CoreSight HW tracing drivers; - I2C subsystem; - IIO subsystem; - IIO ADC drivers; - InfiniBand drivers; - Input Device core drivers; - Input Device (Mouse) drivers; - IOMMU subsystem; - IRQ chip drivers; - M…

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CVE-2026-64264 — fuse-uring: fix EFAULT clobber in fuse_uring_commit

USN-8726-1 — linux, linux-aws, linux-aws-7.0, linux-gcp, linux-gke, linux-hwe-7.0, linux-realtime vulnerabilities