{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43006", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:55.974Z", "datePublished": "2026-05-01T14:15:14.176Z", "dateUpdated": "2026-08-05T12:25:13.184Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:25:13.184Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/rsrc: reject zero-length fixed buffer import\n\nvalidate_fixed_range() admits buf_addr at the exact end of the\nregistered region when len is zero, because the check uses strict\ngreater-than (buf_end > imu->ubuf + imu->len). io_import_fixed()\nthen computes offset == imu->len, which causes the bvec skip logic\nto advance past the last bio_vec entry and read bv_offset from\nout-of-bounds slab memory.\n\nReturn early from io_import_fixed() when len is zero. A zero-length\nimport has no data to transfer and should not walk the bvec array\nat all.\n\n BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0\n Read of size 4 at addr ffff888002bcc254 by task poc/103\n Call Trace:\n io_import_reg_buf+0x697/0x7f0\n io_write_fixed+0xd9/0x250\n __io_issue_sqe+0xad/0x710\n io_issue_sqe+0x7d/0x1100\n io_submit_sqes+0x86a/0x23c0\n __do_sys_io_uring_enter+0xa98/0x1590\n Allocated by task 103:\n The buggy address is located 12 bytes to the right of\n allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)" } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "baseScore": 7.1, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable path is reached through local io_uring syscalls: create a ring, register a fixed buffer, then submit READ_FIXED or WRITE_FIXED. It is not reachable by remote packets or adjacent/physical input.\nAC:L - The trigger is deterministic: use len zero with buf_addr exactly at the end of a registered fixed buffer. No race or attacker-uncontrolled heap state is required to reach the out-of-bounds read.\nPR:L - An unprivileged local user can use io_uring when the upstream sysctl allows it, and buffer registration only requires ordinary user memory within resource limits. No real root or init-namespace capability is required.\nUI:N - After obtaining local execution, the attacker directly invokes io_uring_setup, io_uring_register, and io_uring_enter. No victim action is needed.\nS:U - The vulnerability is in the kernel servicing the attacker's local process and does not cross a separate security authority such as a VM host boundary. Standard local kernel compromise or crash remains Scope Unchanged.\nC:H - The bug performs an attacker-triggered out-of-bounds read from adjacent kernel slab memory while constructing the fixed-buffer bio_vec iterator. Under conservative kernel scoring, this is treated as high confidentiality impact because kernel heap data is read outside the valid object.\nI:N - The demonstrated primitive is an out-of-bounds read of bio_vec metadata, not an out-of-bounds write or use-after-free. I did not find a defensible direct data modification or control-flow overwrite primitive from this zero-length import.\nA:H - The reported path produces a KASAN slab-out-of-bounds BUG in io_import_reg_buf, and the same local trigger can be submitted repeatedly. Kernel oops/panic potential is High availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "io_uring/rsrc.c" ], "versions": [ { "version": "8622b20f23ed165f48b8ca61503a107d17f8d585", "lessThan": "040a1e7e0e2f01851fec1dd2d96906f8636a9f75", "status": "affected", "versionType": "git" }, { "version": "8622b20f23ed165f48b8ca61503a107d17f8d585", "lessThan": "40170fc1a79c1b2e68f09ae6aac687b7305ae6f4", "status": "affected", "versionType": "git" }, { "version": "8622b20f23ed165f48b8ca61503a107d17f8d585", "lessThan": "111a12b422a8cfa93deabaef26fec48237163214", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "io_uring/rsrc.c" ], "versions": [ { "version": "6.15", "status": "affected" }, { "version": "0", "lessThan": "6.15", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.22", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.12", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.19.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/040a1e7e0e2f01851fec1dd2d96906f8636a9f75" }, { "url": "https://git.kernel.org/stable/c/40170fc1a79c1b2e68f09ae6aac687b7305ae6f4" }, { "url": "https://git.kernel.org/stable/c/111a12b422a8cfa93deabaef26fec48237163214" } ], "title": "io_uring/rsrc: reject zero-length fixed buffer import", "x_generator": { "engine": "bippy-1.2.0" } } } }