Bug 2460650 (CVE-2026-31484) - CVE-2026-31484 kernel: io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check
Summary: CVE-2026-31484 kernel: io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check
Keywords:
Status: NEW
Alias: CVE-2026-31484
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-04-22 15:03 UTC by OSIDB Bzimport
Modified: 2026-04-22 18:48 UTC (History)
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Description OSIDB Bzimport 2026-04-22 15:03:06 UTC
In the Linux kernel, the following vulnerability has been resolved:

io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check

__io_uring_show_fdinfo() iterates over pending SQEs and, for 128-byte
SQEs on an IORING_SETUP_SQE_MIXED ring, needs to detect when the second
half of the SQE would be past the end of the sq_sqes array. The current
check tests (++sq_head & sq_mask) == 0, but sq_head is only incremented
when a 128-byte SQE is encountered, not on every iteration. The actual
array index is sq_idx = (i + sq_head) & sq_mask, which can be sq_mask
(the last slot) while the wrap check passes.

Fix by checking sq_idx directly. Keep the sq_head increment so the loop
still skips the second half of the 128-byte SQE on the next iteration.


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