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CVE-2026-52933

io_uring/poll: fix signed comparison in io_poll_get_ownership()

Published: 6/24/2026 Last updated: 6/28/2026 Reserved: 6/9/2026

In the Linux kernel, the following vulnerability has been resolved: io_uring/poll: fix signed comparison in io_poll_get_ownership() io_poll_get_ownership() uses a signed comparison to check whether poll_refs has reached the threshold for the slowpath: if (unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS)) atomic_read() returns int (signed). When IO_POLL_CANCEL_FLAG (BIT(31)) is set in poll_refs, the value becomes negative in signed arithmetic, so the >= 128 comparison always evaluates to false and the slowpath is never taken. Fix this by casting the atomic_read() result to unsigned int before the comparison, so that the cancel flag is treated as a large positive value and correctly triggers the slowpath.

CNA assigner: Linux (416baaa9-dc9f-4396-8d5f-8c081fb06d67) Requested by: n/a

Metrics

Version Score Severity Vector String
3.1 7.8 High CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Opam packages affected (29)

albatross cdrom conf-bpftool conf-libbpf conf-linux-libc-dev core core_unix hvsock mirage-block-unix mm ocaml-probes ortools_solvers orun rawlink rawlink-eio rawlink-lwt restricted shell solo5 solo5-bindings-hvt solo5-bindings-spt solo5-cross-aarch64 solo5-kernel-ukvm tracy-client tuntap uring vhd-format vhd-format-lwt xapi-stdext-unix

Products affected (4)

Product Vendor Version
Linux Linux < publication
Linux Linux < publication
Linux Linux n/a
Linux Linux n/a

References (12)