CVE-2026-74647 (GCVE-0-2026-74647)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-27 12:39
VLAI
Title
misc: fastrpc: Remove buffer from list prior to unmap operation
Summary
In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: Remove buffer from list prior to unmap operation fastrpc_req_munmap_impl() is called to unmap any buffer. The buffer is getting removed from the list after it is unmapped from DSP. This can create potential race conditions if multiple threads invoke unmap concurrently, where one thread may remove the entry from the list while another thread's unmap operation is still ongoing. Fix this by removing the buffer entry from the list before calling the unmap operation. If the unmap fails, the entry is re-added to the list so that userspace can retry the unmap, or alternatively, the buffer will be cleaned up during device release when the DSP process is torn down and all DSP-side mappings are freed along with remaining buffers in the list.
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: 2419e55e532de14fdf336e09e453aa2831c73a25 , < 1edb654b2b41baee2ab5cf418baaf6e57dfbd802 (git)
Affected: 2419e55e532de14fdf336e09e453aa2831c73a25 , < 4716c23c206a2f99ca54ebfdd8b5ba9dd0102240 (git)
Affected: 2419e55e532de14fdf336e09e453aa2831c73a25 , < 99f8de36c84cb9b872157aa6c3578c2480cee4b8 (git)
Affected: 2419e55e532de14fdf336e09e453aa2831c73a25 , < 97273624f7b356eaf8261609a75cfcb8738a165a (git)
Affected: 2419e55e532de14fdf336e09e453aa2831c73a25 , < fe70329055977fc1e8dc6291318d0dd75470795a (git)
Affected: 2419e55e532de14fdf336e09e453aa2831c73a25 , < 9bf22a7d950cec2d1efeca7f16bb20fcca84c36a (git)
Affected: 2419e55e532de14fdf336e09e453aa2831c73a25 , < 0beaa9bd7eb10d9b5e6352ed5161f3f3bbd4c3c5 (git)
Affected: 2419e55e532de14fdf336e09e453aa2831c73a25 , < 6102ceb4eab845743ee57acd3863fbd06e93c927 (git)
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Linux Linux Affected: 5.5
Unaffected: 0 , < 5.5 (semver)
Unaffected: 5.10.267 , ≤ 5.10.* (semver)
Unaffected: 5.15.218 , ≤ 5.15.* (semver)
Unaffected: 6.1.185 , ≤ 6.1.* (semver)
Unaffected: 6.6.152 , ≤ 6.6.* (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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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmisc: fastrpc: Remove buffer from list prior to unmap operation\n\nfastrpc_req_munmap_impl() is called to unmap any buffer. The buffer is\ngetting removed from the list after it is unmapped from DSP. This can\ncreate potential race conditions if multiple threads invoke unmap\nconcurrently, where one thread may remove the entry from the list while\nanother thread\u0027s unmap operation is still ongoing.\n\nFix this by removing the buffer entry from the list before calling the\nunmap operation. If the unmap fails, the entry is re-added to the list\nso that userspace can retry the unmap, or alternatively, the buffer\nwill be cleaned up during device release when the DSP process is torn\ndown and all DSP-side mappings are freed along with remaining buffers\nin the list."
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            "version": "3.1"
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              "value": "AV:L - The flaw is reachable only through local ioctl on a FastRPC misc device (/dev/fastrpc-*); entry is open() plus FASTRPC_IOCTL_MUNMAP after mmap, not via network, Bluetooth, WiFi, or physical buses.\nAC:L - An attacker controls both racing threads and can repeatedly issue concurrent MUNMAP ioctls for the same mapped buffer; the pre-fix window spans the full DSP unmap in fastrpc_req_munmap_impl(), so no attacker-uncontrollable timing is required.\nPR:L - The MMAP/MUNMAP ioctl path has no capable() or init-namespace root check; on Qualcomm/Android phones an unprivileged app that can open the non-secure FastRPC node and create an unsigned user PD can reach this code.\nUI:N - Exploitation needs only attacker-controlled open/ioctl and pthread scheduling against a buffer it already mapped; no separate victim action such as mounting a filesystem or opening a file is required.\nS:U - The race corrupts kernel list/slab state and double-frees struct fastrpc_buf inside the host kernel driver, matching other FastRPC kernel memory-safety CVEs rather than an inherent VM escape or IOMMU boundary bypass.\nC:H - Concurrent unmap can UAF the list node and double-free a fastrpc_buf slab object holding DMA mapping metadata, a classic kernel primitive that can be groomed into arbitrary kernel memory disclosure.\nI:H - Double kfree of fastrpc_buf plus repeated dma_free_coherent on the same coherent mapping enables heap corruption and plausible control-flow or arbitrary-write exploitation in kernel context.\nA:H - Winning the race can trigger list_del on freed memory, slab double-free, or DMA allocator corruption, producing kernel warnings, oopses, or panics that are repeatable via local ioctl flooding."
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    "dateUpdated": "2026-08-27T12:39:52.927Z",
    "state": "PUBLISHED"
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      "product_status:known_affected": "1",
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      "title": "misc: fastrpc: Remove buffer from list prior to unmap operation",
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If the unmap fails, the entry is re-added to the list\\nso that userspace can retry the unmap, or alternatively, the buffer\\nwill be cleaned up during device release when the DSP process is torn\\ndown and all DSP-side mappings are freed along with remaining buffers\\nin the list.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/misc/fastrpc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2419e55e532de14fdf336e09e453aa2831c73a25\",\"lessThan\":\"1edb654b2b41baee2ab5cf418baaf6e57dfbd802\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2419e55e532de14fdf336e09e453aa2831c73a25\",\"lessThan\":\"4716c23c206a2f99ca54ebfdd8b5ba9dd0102240\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2419e55e532de14fdf336e09e453aa2831c73a25\",\"lessThan\":\"99f8de36c84cb9b872157aa6c3578c2480cee4b8\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2419e55e532de14fdf336e09e453aa2831c73a25\",\"lessThan\":\"97273624f7b356eaf8261609a75cfcb8738a165a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2419e55e532de14fdf336e09e453aa2831c73a25\",\"lessThan\":\"fe70329055977fc1e8dc6291318d0dd75470795a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2419e55e532de14fdf336e09e453aa2831c73a25\",\"lessThan\":\"9bf22a7d950cec2d1efeca7f16bb20fcca84c36a\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2419e55e532de14fdf336e09e453aa2831c73a25\",\"lessThan\":\"0beaa9bd7eb10d9b5e6352ed5161f3f3bbd4c3c5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2419e55e532de14fdf336e09e453aa2831c73a25\",\"lessThan\":\"6102ceb4eab845743ee57acd3863fbd06e93c927\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/misc/fastrpc.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.5\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.5\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.267\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.218\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.185\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.152\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.104\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.45\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.9\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"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:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0beaa9bd7eb10d9b5e6352ed5161f3f3bbd4c3c5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/1edb654b2b41baee2ab5cf418baaf6e57dfbd802\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4716c23c206a2f99ca54ebfdd8b5ba9dd0102240\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6102ceb4eab845743ee57acd3863fbd06e93c927\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/97273624f7b356eaf8261609a75cfcb8738a165a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/99f8de36c84cb9b872157aa6c3578c2480cee4b8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9bf22a7d950cec2d1efeca7f16bb20fcca84c36a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/fe70329055977fc1e8dc6291318d0dd75470795a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T08:52:53+00:00",
      "cve": "CVE-2026-74647",
      "id": "CVE-2026-74647",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: misc: fastrpc: Remove buffer from list prior to unmap operation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74647.json",
      "version": "3"
    }
  }
}



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