{"id":"CVE-2026-74306","state":"PUBLISHED","title":"vfio/qat: fix f_pos race in qat_vf_resume_write()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/qat: fix f_pos race in qat_vf_resume_write()\n\nqat_vf_resume_write() checks filp->f_pos before taking migf->lock, but\ncopies into the migration-state buffer after taking the lock and\nre-reading the shared file position.\n\nTwo concurrent writers could therefore pass the bounds check with the\nold offset, then have the second writer copy after the first advanced\nf_pos, writing past the end of the migration-state buffer.\n\nTake migf->lock before doing the boundary checks.","publishedAt":"2026-08-15T05:58:07.313Z","updatedAt":"2026-08-17T05:45:40.501Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bb208810b1abf1c84870cfbe1cc9cf1a1d35c607","status":"affected","lessThan":"6465af0004dc1b067129a26ef44f19cdf13bbce6","versionType":"git"},{"version":"bb208810b1abf1c84870cfbe1cc9cf1a1d35c607","status":"affected","lessThan":"d416dcefdbac90d96b22485fd93f28229ad9984b","versionType":"git"},{"version":"bb208810b1abf1c84870cfbe1cc9cf1a1d35c607","status":"affected","lessThan":"b6fd7a40a66485c8aa8156d8fcf50b95cb8ba281","versionType":"git"},{"version":"bb208810b1abf1c84870cfbe1cc9cf1a1d35c607","status":"affected","lessThan":"4ec5e932e636896e97e4c6a8205b0ac76d52421a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/pci/qat/main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/pci/qat/main.c"]}],"references":["https://git.kernel.org/stable/c/6465af0004dc1b067129a26ef44f19cdf13bbce6","https://git.kernel.org/stable/c/d416dcefdbac90d96b22485fd93f28229ad9984b","https://git.kernel.org/stable/c/b6fd7a40a66485c8aa8156d8fcf50b95cb8ba281","https://git.kernel.org/stable/c/4ec5e932e636896e97e4c6a8205b0ac76d52421a"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74306.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74306","state":"PUBLISHED","datePublished":"2026-08-15T05:58:07.313Z","dateUpdated":"2026-08-17T05:45:40.501Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.883Z"},"containers":{"cna":{"title":"vfio/qat: fix f_pos race in qat_vf_resume_write()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nvfio/qat: fix f_pos race in qat_vf_resume_write()\n\nqat_vf_resume_write() checks filp->f_pos before taking migf->lock, but\ncopies into the migration-state buffer after taking the lock and\nre-reading the shared file position.\n\nTwo concurrent writers could therefore pass the bounds check with the\nold offset, then have the second writer copy after the first advanced\nf_pos, writing past the end of the migration-state buffer.\n\nTake migf->lock before doing the boundary checks."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"bb208810b1abf1c84870cfbe1cc9cf1a1d35c607","status":"affected","lessThan":"6465af0004dc1b067129a26ef44f19cdf13bbce6","versionType":"git"},{"version":"bb208810b1abf1c84870cfbe1cc9cf1a1d35c607","status":"affected","lessThan":"d416dcefdbac90d96b22485fd93f28229ad9984b","versionType":"git"},{"version":"bb208810b1abf1c84870cfbe1cc9cf1a1d35c607","status":"affected","lessThan":"b6fd7a40a66485c8aa8156d8fcf50b95cb8ba281","versionType":"git"},{"version":"bb208810b1abf1c84870cfbe1cc9cf1a1d35c607","status":"affected","lessThan":"4ec5e932e636896e97e4c6a8205b0ac76d52421a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/pci/qat/main.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.97","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.40","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.5","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/vfio/pci/qat/main.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/6465af0004dc1b067129a26ef44f19cdf13bbce6"},{"url":"https://git.kernel.org/stable/c/d416dcefdbac90d96b22485fd93f28229ad9984b"},{"url":"https://git.kernel.org/stable/c/b6fd7a40a66485c8aa8156d8fcf50b95cb8ba281"},{"url":"https://git.kernel.org/stable/c/4ec5e932e636896e97e4c6a8205b0ac76d52421a"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","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'd 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->state, 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."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:45:40.501Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.97"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}