ublk: reset per-IO canceled flag on each fetch

Summary

In the Linux kernel, the following vulnerability has been resolved: ublk: reset per-IO canceled flag on each fetch If a ublk server starts recovering devices but dies before issuing fetch commands for all IOs, cancellation of the fetch commands that were successfully issued may never complete. This is because the per-IO canceled flag can remain set even after the fetch for that IO has been submitted - the per-IO canceled flags for all IOs in a queue are reset together only once all IOs for that queue have been fetched. So if a nonempty proper subset of the IOs for a queue are fetched when the ublk server dies, the IOs in that subset will never successfully be canceled, as their canceled flags remain set, and this prevents ublk_cancel_cmd from actually calling io_uring_cmd_done on the commands, despite the fact that they are outstanding. Fix this by resetting the per-IO cancel flags immediately when each IO is fetched instead of waiting for all IOs for the queue (which may never happen).

Timeline

1. Jun 24, 2026, 4:30 PM UTCCVE published
2. Oct 15, 2026, 10:07 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 728cbac5fe219d3b8a21a0688a08f2b7f8aeda2b · fixed in de05e37d02f3f33ebca4967164e54f5fea809d86; From 728cbac5fe219d3b8a21a0688a08f2b7f8aeda2b · fixed in 63335e5a67d89bb7cb9b023bbb3785896587a648; From 728cbac5fe219d3b8a21a0688a08f2b7f8aeda2b · fixed in 0842186d2c4e67d2f8c8c2d1d779e8acffd41b5b; From 6.14.6 · fixed in 6.15

• Linux Linux

  6.15

• KernelLinux

  From 6.15.0 · fixed in 6.18.57; From 6.19.0 · fixed in 7.0.10

References 3