CVE-2026-99266

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

cve-program · severity unknownCVSS unknownCheck source for fixed versionsKEV status unknown

Original advisory

Historical advisory recorded 3 Nov 2026 21:57:16 UTC. Read the latest advisory.

cve-program · CVE-2026-99266

Published

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.

Read the publisher's advisory

Affected versions, risk and source history

cve-program · CVE-2026-99266

Published

Linux

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "io_uring/zcrx.c"
                    ],
                    "versions": [
                        {
                            "version": "11ed914bbf948c4a37248f2876973ac18014056d",
                            "lessThan": "9bfb315e2d0907fbcaf5d0453dd6d873c9aa8d5b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "11ed914bbf948c4a37248f2876973ac18014056d",
                            "lessThan": "51f4ee29bf0564e6ae7d3540693a9bc1dd2c8fd7",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "11ed914bbf948c4a37248f2876973ac18014056d",
                            "lessThan": "ab4536bf2e5617b04f2d9396f06393c7bbfb071d",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

Linux

Vendor product

Publisher's version information

Shown as published. These rules are not interpreted as NuGet package version ranges.

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "io_uring/zcrx.c"
                    ],
                    "versions": [
                        {
                            "version": "6.15",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.15",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.60",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.14",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.4-rc1",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }

Original source record · Cite this exact observation · Complete original publisher JSON