CVE-2026-99266 PUBLISHED

io_uring/zcrx: fix buffer offsets in areas above 4GB

Assigner: Linux
Reserved: 25.09.2026 Published: 03.11.2026 Updated: 03.11.2026

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

io_uring/zcrx: fix buffer offsets in areas above 4GB

io_zcrx_queue_cqe() computes the offset of the buffer in its area from net_iov_idx(), which is an unsigned int, so the shift is done in 32 bits and only the result is widened to the u64 that goes into the CQE. An area can be up to 1TB in size. For every niov beyond the first 4GB the CQE points the application at a buffer 4GB, or a multiple of that, below the one which has the data. It reads the wrong data, and then returns a buffer it doesn't own via the refill queue while the real one is never given back.

Product Status

Vendor Linux
Product Linux
Versions Default: unaffected
  • affected from 11ed914bbf948c4a37248f2876973ac18014056d to 9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b (excl.)
  • affected from 11ed914bbf948c4a37248f2876973ac18014056d to 51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7 (excl.)
Vendor Linux
Product Linux
Versions Default: affected
  • Version 6.15 is affected
  • unaffected from 0 to 6.15 (excl.)
  • unaffected from 6.18.60 to 6.18.* (incl.)
  • unaffected from 7.2.14 to 7.2.* (incl.)

References