CVE-2026-31774 (GCVE-0-2026-31774)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:15 – Updated: 2026-05-11 22:15
VLAI?
Title
io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs() sqe->len is __u32 but gets stored into sr->len which is int. When userspace passes sqe->len values exceeding INT_MAX (e.g. 0xFFFFFFFF), sr->len overflows to a negative value. This negative value propagates through the bundle recv/send path: 1. io_recv(): sel.val = sr->len (ssize_t gets -1) 2. io_recv_buf_select(): arg.max_len = sel->val (size_t gets 0xFFFFFFFFFFFFFFFF) 3. io_ring_buffers_peek(): buf->len is not clamped because max_len is astronomically large 4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs() 5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1, causing ret to increase instead of decrease, creating an infinite loop that reads past the allocated iov[] array This results in a slab-out-of-bounds read in io_bundle_nbufs() from the kmalloc-64 slab, as nbufs increments past the allocated iovec entries. BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160 Read of size 8 at addr ffff888100ae05c8 by task exp/145 Call Trace: io_bundle_nbufs+0x128/0x160 io_recv_finish+0x117/0xe20 io_recv+0x2db/0x1160 Fix this by rejecting negative sr->len values early in both io_sendmsg_prep() and io_recvmsg_prep(). Since sqe->len is __u32, any value > INT_MAX indicates overflow and is not a valid length.
Severity ?
7.1 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: a05d1f625c7aa681d8816bc0f10089289ad07aad , < 90ced24c500ad4e129e9e34b7e56fd7849e350b6 (git)
Affected: a05d1f625c7aa681d8816bc0f10089289ad07aad , < c314b405dcc4d8b9041124f928f81715d6328bec (git)
Affected: a05d1f625c7aa681d8816bc0f10089289ad07aad , < 1b655cd311344117d3052f6552cb20d9901c9d7c (git)
Affected: a05d1f625c7aa681d8816bc0f10089289ad07aad , < b948f9d5d3057b01188e36664e7c7604d1c8ecb5 (git)
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    Linux Linux Affected: 6.10
Unaffected: 0 , < 6.10 (semver)
Unaffected: 6.12.81 , ≤ 6.12.* (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()\n\nsqe-\u003elen is __u32 but gets stored into sr-\u003elen which is int. When\nuserspace passes sqe-\u003elen values exceeding INT_MAX (e.g. 0xFFFFFFFF),\nsr-\u003elen overflows to a negative value. This negative value propagates\nthrough the bundle recv/send path:\n\n  1. io_recv(): sel.val = sr-\u003elen (ssize_t gets -1)\n  2. io_recv_buf_select(): arg.max_len = sel-\u003eval (size_t gets\n     0xFFFFFFFFFFFFFFFF)\n  3. io_ring_buffers_peek(): buf-\u003elen is not clamped because max_len\n     is astronomically large\n  4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs()\n  5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1,\n     causing ret to increase instead of decrease, creating an\n     infinite loop that reads past the allocated iov[] array\n\nThis results in a slab-out-of-bounds read in io_bundle_nbufs() from\nthe kmalloc-64 slab, as nbufs increments past the allocated iovec\nentries.\n\n  BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160\n  Read of size 8 at addr ffff888100ae05c8 by task exp/145\n  Call Trace:\n   io_bundle_nbufs+0x128/0x160\n   io_recv_finish+0x117/0xe20\n   io_recv+0x2db/0x1160\n\nFix this by rejecting negative sr-\u003elen values early in both\nio_sendmsg_prep() and io_recvmsg_prep(). Since sqe-\u003elen is __u32,\nany value \u003e INT_MAX indicates overflow and is not a valid length."
        }
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            "version": "3.1"
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        "dateUpdated": "2026-05-11T22:15:33.122Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/b948f9d5d3057b01188e36664e7c7604d1c8ecb5"
        }
      ],
      "title": "io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()",
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    "datePublished": "2026-05-01T14:15:02.903Z",
    "dateReserved": "2026-03-09T15:48:24.140Z",
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    "state": "PUBLISHED"
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