CVE-2026-31484 io_uring/fdinfo: fix OOB read in SQE_MIXED wrap check

What is CVE-2026-31484?

CVE-2026-31484 is a high-severity vulnerability in Linux kernel, published on 22 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-125

Which versions are affected by CVE-2026-31484?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-31484?

Apply the vendor's patch.

Is CVE-2026-31484 being exploited?

There is no known exploitation of CVE-2026-31484 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-31484, GHSA-q2h9-rpjj-p4gc, UBUNTU-CVE-2026-31484.