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CVE-2026-74306 (GCVE-0-2026-74306)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:58 – Updated: 2026-08-17 05:45
VLAI
Title
vfio/qat: fix f_pos race in qat_vf_resume_write()
Summary
In the Linux kernel, the following vulnerability has been resolved: vfio/qat: fix f_pos race in qat_vf_resume_write() qat_vf_resume_write() checks filp->f_pos before taking migf->lock, but copies into the migration-state buffer after taking the lock and re-reading the shared file position. Two concurrent writers could therefore pass the bounds check with the old offset, then have the second writer copy after the first advanced f_pos, writing past the end of the migration-state buffer. Take migf->lock before doing the boundary checks.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: bb208810b1abf1c84870cfbe1cc9cf1a1d35c607 , < 6465af0004dc1b067129a26ef44f19cdf13bbce6 (git)
Affected: bb208810b1abf1c84870cfbe1cc9cf1a1d35c607 , < d416dcefdbac90d96b22485fd93f28229ad9984b (git)
Affected: bb208810b1abf1c84870cfbe1cc9cf1a1d35c607 , < b6fd7a40a66485c8aa8156d8fcf50b95cb8ba281 (git)
Affected: bb208810b1abf1c84870cfbe1cc9cf1a1d35c607 , < 4ec5e932e636896e97e4c6a8205b0ac76d52421a (git)
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Linux Linux Affected: 6.10
Unaffected: 0 , < 6.10 (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
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        }
      ],
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            "version": "3.1"
          },
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              "value": "AV:L - Exploitation requires local write() syscalls on a VFIO live-migration resume fd returned by VFIO_DEVICE_FEATURE_MIG_DEVICE_STATE ioctl on an opened QAT VFIO PCI device; there is no network, adjacent-wireless, or physical-device attack path to this code.\nAC:L - An attacker with the migration fd controls both racing writers (e.g., concurrent threads or dup\u0027d fds sharing f_pos) and can repeatedly trigger the TOCTOU window near the buffer end until the overflow succeeds; no uncontrollable victim timing or memory layout is required.\nPR:L - Exploitation requires only local access to an assigned Intel QAT VFIO device migration fd (typical QEMU/cloud/HPC VFIO clients), not real root in the init namespace; capabilities like CAP_NET_ADMIN via user namespaces do not grant this path.\nUI:N - No victim interaction is required; the attacker drives VFIO migration state transitions and concurrent writes to the resume fd programmatically without any separate user or administrator action during exploitation.\nS:U - The flaw corrupts host kernel heap memory from a VFIO client context and does not by itself cross an IOMMU, VM-guest, or other distinct security authority boundary; impact remains host kernel compromise/DoS within the same authority.\nC:H - The race yields an attacker-controlled heap out-of-bounds write past the 4096-byte migration-state kmalloc buffer, which can corrupt adjacent kernel objects and be leveraged for arbitrary kernel memory disclosure, not merely a bounded leak.\nI:H - copy_from_user() writes attacker-controlled data beyond mig_dev-\u003estate, enabling heap corruption and potential arbitrary kernel write or code-execution primitives through grooming of adjacent kmalloc objects.\nA:H - Heap corruption from the out-of-bounds write can immediately panic or oops the kernel or destabilize the system even when full exploitation is not attempted, satisfying high availability impact for kernel memory corruption."
            }
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        "dateUpdated": "2026-08-17T05:45:40.501Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/6465af0004dc1b067129a26ef44f19cdf13bbce6"
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          "url": "https://git.kernel.org/stable/c/4ec5e932e636896e97e4c6a8205b0ac76d52421a"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74306",
    "datePublished": "2026-08-15T05:58:07.313Z",
    "dateReserved": "2026-08-15T05:44:03.883Z",
    "dateUpdated": "2026-08-17T05:45:40.501Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-20T16:37:55+00:00",
      "cve": "CVE-2026-74306",
      "id": "CVE-2026-74306",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: vfio/qat: fix f_pos race in qat_vf_resume_write()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74306.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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