CVE Catalog

CVE-2026-64426

Low risk· EPSS 6%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.17%

6th percentile - higher than 6% of all known CVEs

Summary

In the Linux kernel, the io_uring subsystem has a file reference leak in the NOP operation. When a NOP request is submitted with the IOSQE_FIXED_FILE flag but without IORING_NOP_FIXED_FILE, the file is acquired via fget() and never released, causing a memory leak. The fix decides file acquisition based on the REQ_F_FIXED_FILE flag, as in other operations.

Risk Assessment

The organization may experience memory leaks in the system, which over time can lead to resource exhaustion, reduced performance, or system crashes.

Recommendation

It is recommended to update the Linux kernel to a version containing the fix for CVE-2026-64426 to prevent memory leaks in io_uring.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: io_uring/nop: fix file reference leak with IOSQE_FIXED_FILE NOP file-acquisition support choses between a fixed (registered) file and a normal fget()'d file based on its own IORING_NOP_FIXED_FILE flag in sqe->nop_flags. However, a request's REQ_F_FIXED_FILE is set independently from the generic IOSQE_FIXED_FILE sqe flag during request init, before the issue handler runs. If a NOP is submitted with IOSQE_FIXED_FILE set (so REQ_F_FIXED_FILE is set) but without IORING_NOP_FIXED_FILE, io_nop() takes the normal path and grabs a real reference via io_file_get_normal(). On completion, io_put_file() only drops the reference when REQ_F_FIXED_FILE is clear, so the fget()'d file is never released and leaks: BUG: memory leak unreferenced object 0xffff88800f42c240 (size 176): kmem_cache_alloc_noprof+0x358/0x440 alloc_empty_file+0x57/0x180 path_openat+0x44/0x1e50 do_file_open+0x121/0x200 do_sys_openat2+0xa7/0x150 __x64_sys_openat+0x82/0xf0 Decide between fixed and normal file acquisition from REQ_F_FIXED_FILE, the same way io_assign_file() does for every other opcode, and fold IORING_NOP_FIXED_FILE into REQ_F_FIXED_FILE at prep time.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS