{"id":"CVE-2026-72491","title":"net/9p: fix race condition on rdma->state in trans_rdma.c","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/9p: fix race condition on rdma->state in trans_rdma.c\n\nThe rdma->state field is modified without holding req_lock in both\nrecv_done() and p9_cm_event_handler(), whi…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 4cee2b8766045059d5e0b8114837b4a8efe827ac","Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 5424138848eb7d7d8a7196676e90a2cbf2142454","Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 3970a19a80de530b801b6256354d4a529a9a2d6c","Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 8aadc136d8e8d8fc95d7982d213cfe2234dfcf2b","Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 151f8cf5b23d8a534d884432a82a6d54d5a61989","Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 13bf9879b778b2f4b260b45bed18f31806120d1e","Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < ebbcbe5c0db215feecc17def06178da443f4eea6","Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 7d54894a1ee265a72d70f7cae1da6cc774cccc71","Linux 3479b3c35e82ed10aa0ca2ee9e78c4eded06ba62","Linux c01ddaa54d7411e964ffd250c018d8469c5852f2","Linux 9e69c673fe077b8dc491cd8406c9bdcb1f76dee2","Linux e48e7e27e4dfd00c81e0381e7cee610cce021452","Linux >= 4.4.185 < 4.5","Linux >= 4.9.185 < 4.10","Linux >= 4.14.132 < 4.15","Linux >= 4.19.57 < 4.20","Linux 4.20"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T18:50:50.731501Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:55:26.515Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72491","references":[{"url":"https://git.kernel.org/stable/c/4cee2b8766045059d5e0b8114837b4a8efe827ac"},{"url":"https://git.kernel.org/stable/c/5424138848eb7d7d8a7196676e90a2cbf2142454"},{"url":"https://git.kernel.org/stable/c/3970a19a80de530b801b6256354d4a529a9a2d6c"},{"url":"https://git.kernel.org/stable/c/8aadc136d8e8d8fc95d7982d213cfe2234dfcf2b"},{"url":"https://git.kernel.org/stable/c/151f8cf5b23d8a534d884432a82a6d54d5a61989"},{"url":"https://git.kernel.org/stable/c/13bf9879b778b2f4b260b45bed18f31806120d1e"},{"url":"https://git.kernel.org/stable/c/ebbcbe5c0db215feecc17def06178da443f4eea6"},{"url":"https://git.kernel.org/stable/c/7d54894a1ee265a72d70f7cae1da6cc774cccc71"}],"tags":["cve.org"],"epss":0.00734,"epssPercentile":0.53476,"ingestedAt":"2026-10-16T19:46:24.391Z","slug":"CVE-2026-72491","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnet/9p: fix race condition on rdma->state in trans_rdma.c\n\nThe rdma->state field is modified without holding req_lock in both\nrecv_done() and p9_cm_event_handler(), while rdma_request() accesses\nthe same field under the req_lock spinlock. This inconsistent locking\ncreates a race condition:\n\n- recv_done() running in softirq completion context sets\n  rdma->state = P9_RDMA_FLUSHING without acquiring req_lock\n\n- p9_cm_event_handler() modifies rdma->state at multiple points\n  (ADDR_RESOLVED, ROUTE_RESOLVED, ESTABLISHED, CLOSED) without\n  req_lock\n\n- rdma_request() uses spin_lock_irqsave(&rdma->req_lock, flags) to\n  protect the read-modify-write of rdma->state\n\nThe race can cause lost state transitions: recv_done() or the CM\nevent handler could set state to FLUSHING/CLOSED while rdma_request()\nis concurrently checking or modifying state under the lock, leading to\nthe FLUSHING transition being silently overwritten by CLOSING. This\ncorrupts the connection state machine and can cause use-after-free on\nRDMA request objects during teardown.\n\nFix by adding req_lock protection to all rdma->state modifications in\nrecv_done() and p9_cm_event_handler(), matching the pattern already\nused in rdma_request(). Use spin_lock_irqsave/spin_unlock_irqrestore\nin the CM event handler since it can race with recv_done() which runs\nin softirq context.\n\nTested with a kernel module that races two threads (simulating\nrdma_request and recv_done/CM handler) on rdma->state with proper\nlocking: 5.5M+ FLUSHING writes over 27M iterations with 0 lost\ntransitions.\n\n## Affected\n\n- `Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 4cee2b8766045059d5e0b8114837b4a8efe827ac`\n- `Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 5424138848eb7d7d8a7196676e90a2cbf2142454`\n- `Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 3970a19a80de530b801b6256354d4a529a9a2d6c`\n- `Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 8aadc136d8e8d8fc95d7982d213cfe2234dfcf2b`\n- `Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 151f8cf5b23d8a534d884432a82a6d54d5a61989`\n- `Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 13bf9879b778b2f4b260b45bed18f31806120d1e`\n- `Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < ebbcbe5c0db215feecc17def06178da443f4eea6`\n- `Linux >= 473c7dd1d7b59ff8f88a5154737e3eac78a96e5b < 7d54894a1ee265a72d70f7cae1da6cc774cccc71`\n- `Linux 3479b3c35e82ed10aa0ca2ee9e78c4eded06ba62`\n- `Linux c01ddaa54d7411e964ffd250c018d8469c5852f2`\n- `Linux 9e69c673fe077b8dc491cd8406c9bdcb1f76dee2`\n- `Linux e48e7e27e4dfd00c81e0381e7cee610cce021452`\n- `Linux >= 4.4.185 < 4.5`\n- `Linux >= 4.9.185 < 4.10`\n- `Linux >= 4.14.132 < 4.15`\n- `Linux >= 4.19.57 < 4.20`\n- `Linux 4.20`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}