{"id":"CVE-2026-68330","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-68330","summary":"net: airoha: Fix DMA direction for NPU mailbox buffer","details":"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— 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.","published":"2026-08-10T12:03:06.542Z","modified":"2026-08-14T04:04:12.292976567Z","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.18.42"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/4c4d866a64f36718cbcdf20add372a599dd44311"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6f884eb87a79e0c482baef2ad96c96b81d024235"},{"type":"WEB","url":"https://git.kernel.org/stable/c/76fc5604308a109bf5838c2a0a0eb3ac6819f1ea"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68330.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68330"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-14T04:04:12.292976567Z"}}