CVE-2026-68330 (GCVE-0-2026-68330)

Vulnerability from cvelistv5 – Published: 2026-08-10 12:03 – Updated: 2026-08-17 05:03
VLAI
Title
net: airoha: Fix DMA direction for NPU mailbox buffer
Summary
In the Linux kernel, the following vulnerability has been resolved: net: airoha: Fix DMA direction for NPU mailbox buffer airoha_npu_send_msg() always maps the mailbox buffer with DMA_TO_DEVICE, but some callers expect the NPU to write response data back into the same buffer: - airoha_npu_wlan_msg_get() (NPU_OP_GET): NPU writes response into the buffer, then the caller reads it via memcpy() - airoha_npu_ppe_stats_setup() (NPU_OP_SET): NPU writes back npu_stats_addr field in the response On non-cache-coherent architectures like EN7581 (Cortex-A53 without hardware cache coherency for NPU DMA), DMA_TO_DEVICE unmap is a no-op — it does not invalidate the CPU cache. If the NPU-written cache line is still present in the CPU cache when the caller reads the buffer, the CPU observes stale data instead of the NPU response. This is a timing-sensitive bug: small mailbox buffers (~24 bytes) typically fit in a single cache line and may survive in the cache until the caller reads them, producing silent data corruption rather than a crash. The bug is more likely to trigger when the caller reads the response immediately after dma_unmap_single() without intervening cache-evicting operations. Fix by using DMA_BIDIRECTIONAL for both map and unmap, which ensures dma_unmap_single() invalidates the CPU cache on non-coherent systems. The mailbox buffers are small so there is no performance concern.
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: c52918744ee1e49cea86622a2633b9782446428f , < 76fc5604308a109bf5838c2a0a0eb3ac6819f1ea (git)
Affected: c52918744ee1e49cea86622a2633b9782446428f , < 4c4d866a64f36718cbcdf20add372a599dd44311 (git)
Affected: c52918744ee1e49cea86622a2633b9782446428f , < 6f884eb87a79e0c482baef2ad96c96b81d024235 (git)
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Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/net/ethernet/airoha/airoha_npu.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: airoha: Fix DMA direction for NPU mailbox buffer\n\nairoha_npu_send_msg() always maps the mailbox buffer with DMA_TO_DEVICE,\nbut some callers expect the NPU to write response data back into the\nsame buffer:\n\n- airoha_npu_wlan_msg_get() (NPU_OP_GET): NPU writes response into\n  the buffer, then the caller reads it via memcpy()\n- airoha_npu_ppe_stats_setup() (NPU_OP_SET): NPU writes back\n  npu_stats_addr field in the response\n\nOn non-cache-coherent architectures like EN7581 (Cortex-A53 without\nhardware cache coherency for NPU DMA), DMA_TO_DEVICE unmap is a no-op\n\u2014 it does not invalidate the CPU cache. If the NPU-written cache line\nis still present in the CPU cache when the caller reads the buffer,\nthe CPU observes stale data instead of the NPU response.\n\nThis is a timing-sensitive bug: small mailbox buffers (~24 bytes)\ntypically fit in a single cache line and may survive in the cache\nuntil the caller reads them, producing silent data corruption rather\nthan a crash. The bug is more likely to trigger when the caller reads\nthe response immediately after dma_unmap_single() without intervening\ncache-evicting operations.\n\nFix by using DMA_BIDIRECTIONAL for both map and unmap, which ensures\ndma_unmap_single() invalidates the CPU cache on non-coherent systems.\nThe mailbox buffers are small so there is no performance concern."
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              "value": "AV:L - The defect is a host-side DMA-direction/cache-coherency error in the airoha NPU mailbox path; it is exercised through local driver probe, interface bring-up, and hardware flow-offload configuration, not by any remotely supplied packet data.\nAC:L - Each mailbox exchange on a non-coherent EN7581 SoC can return stale cache contents, and the affected setup paths can be re-entered repeatedly (offload teardown/re-setup, interface bring-up) while cache pressure is influenced by local activity, so the faulty read is reliably reproducible.\nPR:L - The vulnerable mailbox exchanges run during driver initialization and offload setup on these router SoCs; the lowest plausible trigger is an ordinary local user provoking interface/offload (re)initialization, and the probe-time instance requires no privileges at all.\nUI:N - No victim action is needed \u2014 the stale-response reads happen automatically during NPU/PPE/WLAN initialization and offload setup.\nS:U - The corrupted addresses and misdirected accesses stay within the kernel\u0027s own security authority on the affected SoC; no hypervisor or IOMMU security boundary is crossed by the defect itself.\nC:H - A stale npu_stats_addr causes devm_ioremap() of an unintended physical address whose contents are then read via memcpy_fromio() and exposed to userspace as flow-offload statistics, disclosing memory the driver was never meant to read.\nI:H - Stale responses are used as real addresses: memset_io() zeroes an unintended ioremapped region, and stale RXDESC_BASE values are written into WiFi ring descriptor base registers, causing device DMA writes into memory the driver does not own.\nA:H - Mapping and accessing a bogus physical address, and pointing hardware DMA rings at an invalid base, produce bus errors, descriptor-processing failures and memory corruption that lead to oops or system hang."
            }
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        "dateUpdated": "2026-08-17T05:03:28.769Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/4c4d866a64f36718cbcdf20add372a599dd44311"
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        {
          "url": "https://git.kernel.org/stable/c/6f884eb87a79e0c482baef2ad96c96b81d024235"
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    "datePublished": "2026-08-10T12:03:06.542Z",
    "dateReserved": "2026-07-30T09:28:09.383Z",
    "dateUpdated": "2026-08-17T05:03:28.769Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-26T13:39:09+00:00",
      "cve": "CVE-2026-68330",
      "id": "CVE-2026-68330",
      "initial_release_date": "2026-08-10T00:00:00+00:00",
      "product_status:known_not_affected": "276",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: net: airoha: Fix DMA direction for NPU mailbox buffer",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68330.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-11T23:47:39Z",
      "cve": "CVE-2026-68330",
      "id": "CVE-2026-68330",
      "initial_release_date": "2026-08-11T23:47:39Z",
      "product_status:known_not_affected": "296",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68330",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68330.json",
      "version": "2"
    }
  }
}



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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.

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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.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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