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CVE-2026-74712 (GCVE-0-2026-74712)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:33 – Updated: 2026-08-25 05:41
VLAI
Title
vdpa/mlx5: Fix buffer length in create_direct_keys()
Summary
In the Linux kernel, the following vulnerability has been resolved: vdpa/mlx5: Fix buffer length in create_direct_keys() We have seen in our CI the following KASAN message: BUG: KASAN: slab-out-of-bounds in cmd_exec+0x550/0xca0 [mlx5_core] Read of size 272 at addr 0000000176795020 by task qemu-system-s39/82764 [...] [<000011388ab3a7a0>] cmd_exec+0x550/0xca0 [mlx5_core] [<000011388ab3b61c>] mlx5_cmd_exec_cb+0x25c/0x4f0 [mlx5_core] [<000011388b21e82e>] mlx5_vdpa_exec_async_cmds+0x22e/0x5e0 [mlx5_vdpa] [<000011388b21fd44>] create_direct_keys+0x954/0xef0 [mlx5_vdpa] [...] The buggy address is located 4128 bytes inside of allocated 4384-byte region [0000000176794000, 0000000176795120) So in essence we read 16 bytes beyond 4384-byte allocation. create_direct_keys calculates the pointer and length for in and out buffers. The size calculation for in includes the entire structure size (out + in + mtt[]) but the pointer passed to cmd_exec points only to the 'in' field, skipping the 'out' field. This causes mlx5_copy_to_msg() to read beyond the allocated buffer by sizeof(out) bytes when copying command data. Properly calculate the input size to match the pointer and allocation size.
Severity
9.3 (Critical)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0071b138d44af4296bf871e6624369ce697b4b15 , < ec3bb289cf19d526224117d5d450a5fd9cbd5ab2 (git)
Affected: 0071b138d44af4296bf871e6624369ce697b4b15 , < cde8931a25392670dd59a0acfcab87a830ab66c5 (git)
Affected: 0071b138d44af4296bf871e6624369ce697b4b15 , < 6c8a9f7bc00301e533a5366384f3070a8e7f8430 (git)
Affected: 0071b138d44af4296bf871e6624369ce697b4b15 , < 727e1f569855df83579edbd73dcb4a0723543a12 (git)
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Linux Linux Affected: 6.12
Unaffected: 0 , < 6.12 (semver)
Unaffected: 6.12.104 , ≤ 6.12.* (semver)
Unaffected: 6.18.45 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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          "product": "Linux",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvdpa/mlx5: Fix buffer length in create_direct_keys()\n\nWe have seen in our CI the following KASAN message:\nBUG: KASAN: slab-out-of-bounds in cmd_exec+0x550/0xca0 [mlx5_core]\nRead of size 272 at addr 0000000176795020 by task qemu-system-s39/82764\n[...]\n[\u003c000011388ab3a7a0\u003e] cmd_exec+0x550/0xca0 [mlx5_core]\n[\u003c000011388ab3b61c\u003e] mlx5_cmd_exec_cb+0x25c/0x4f0 [mlx5_core]\n[\u003c000011388b21e82e\u003e] mlx5_vdpa_exec_async_cmds+0x22e/0x5e0 [mlx5_vdpa]\n[\u003c000011388b21fd44\u003e] create_direct_keys+0x954/0xef0 [mlx5_vdpa]\n[...]\nThe buggy address is located 4128 bytes inside of\nallocated 4384-byte region [0000000176794000, 0000000176795120)\n\nSo in essence we read 16 bytes beyond 4384-byte allocation.\ncreate_direct_keys calculates the pointer and length for in and out\nbuffers.\nThe size calculation for in includes the entire structure\nsize (out + in + mtt[]) but the pointer passed to cmd_exec points only\nto the \u0027in\u0027 field, skipping the \u0027out\u0027 field.\n\nThis causes mlx5_copy_to_msg() to read beyond the allocated buffer\nby sizeof(out) bytes when copying command data.\n\nProperly calculate the input size to match the pointer and allocation size."
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              "value": "AV:L - The bug is reached when host vDPA memory keys are created during IOTLB/set_map handling on /dev/vhost-vdpa (ioctl/write from QEMU/vhost), not from remote network packet processing; worst case is a co-tenant VM guest driving host QEMU virtio memory updates on the same mlx5 vDPA host.\nAC:L - Once mlx5 vDPA user MR setup runs, create_direct_keys() always passes an oversized inlen to mlx5_cmd_exec_cb(), deterministically causing mlx5_copy_to_msg() to read past the slab allocation; no race or victim state is required beyond normal virtio memory mapping.\nPR:N - In cloud mlx5 virtio-vDPA deployments a malicious VM tenant needs no host credentials\u2014normal guest virtio-net bring-up causes QEMU to issue vhost IOTLB updates that invoke mlx5_vdpa_set_map() and create_user_mr() on the host without CAP_NET_ADMIN or root in the host init namespace.\nUI:N - Exploitation requires only automated virtio driver initialization and memory table updates; no additional victim clicks, mounts, or manual actions are needed beyond provisioning a vDPA-backed VM, which is the intended operational path.\nS:C - The vulnerable mlx5 vDPA code runs in the hypervisor host kernel while the practical attacker is a guest VM tenant; successful slab out-of-bounds reads and corrupted firmware commands cross the guest/host virtualization boundary per KVM guest-to-host guidance.\nC:H - Incorrect inlen makes mlx5_copy_to_msg() perform a slab out-of-bounds read (KASAN-reported) of adjacent kernel heap memory, copying leaked bytes into CREATE_MKEY commands and enabling arbitrary kernel information disclosure, not a bounded benign leak.\nI:H - The over-read injects adjacent heap contents into firmware CREATE_MKEY command buffers, corrupting memory-key setup data sent to the mlx5 device; this is exploitable kernel memory corruption that can alter device DMA mappings and enable further control, not a read-only crash.\nA:H - The flaw triggers a KASAN slab-out-of-bounds fault in mlx5_core cmd_exec() during normal MR creation; such heap corruption commonly causes kernel oops/panic and can also destabilize vDPA networking on repeated virtio memory remaps."
            }
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        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/727e1f569855df83579edbd73dcb4a0723543a12"
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    "cveId": "CVE-2026-74712",
    "datePublished": "2026-08-22T15:33:08.392Z",
    "dateReserved": "2026-08-15T05:44:03.928Z",
    "dateUpdated": "2026-08-25T05:41:54.897Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T08:55:27+00:00",
      "cve": "CVE-2026-74712",
      "id": "CVE-2026-74712",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: vdpa/mlx5: Fix buffer length in create_direct_keys()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74712.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-10T16:30:23Z",
      "cve": "CVE-2026-74712",
      "id": "CVE-2026-74712",
      "initial_release_date": "2026-08-23T00:04:09Z",
      "product_status:first_fixed": "65",
      "product_status:known_affected": "55",
      "product_status:known_not_affected": "286",
      "product_status:recommended": "18",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74712",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74712.json",
      "version": "7"
    }
  }
}



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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
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