PT-2026-64647 · Linux · Linux

CVE-2026-64426 · Publicado 2026-07-25 · Atualizado 2026-07-25

Mitre

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.

Identificadores relacionados

CVE-2026-64426

Produtos afetados

Linux

Referências · 4

• https://git.kernel.org/stable/c/722869fcff598fad20d5ab79c305897a7534708b · Nota
• https://git.kernel.org/stable/c/2564ca2e31bd8ee8348362941af2ee4671e487ca · Nota
• https://git.kernel.org/stable/c/7267717f35787167fcce4bc14f6ef3fa06682dcf · Nota
• https://nvd.nist.gov/vuln/detail/CVE-2026-64426 · Nota de Segurança