{"id":"CVE-2026-98366","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: validate access flags before swapping the MR's PD\n\nrxe_rereg_user_mr() reassigns mr->ibmr.pd first and only then\nvalidates the IB_MR_REREG_ACCESS argument:\n\n\t…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: validate access flags before swapping the MR's PD\n\nrxe_rereg_user_mr() reassigns mr->ibmr.pd first and only then\nvalidates the IB_MR_REREG_ACCESS argument:\n\n\t…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c < 08f12745cb72981aa2cabe214af0c7a42a856f0a","Linux >= 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c < 7230cc456d4bb2221c20c5f1d22b38b8576aa16f","Linux >= 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c < fe602c91a52e161ace4afd5bdb8f33270c554c6f","Linux >= 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c < 4dd7a53f1c5b44693c26dac4b9b5bd5bb9d604c8","Linux >= 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c < ae36a5b609ae79f4de966328b78d2584be9719a4","Linux 6.5"],"published":"2026-10-06","updated":"2026-10-06","sourceUpdated":"2026-10-06T09:18:30.823","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-98366","references":[{"url":"https://git.kernel.org/stable/c/08f12745cb72981aa2cabe214af0c7a42a856f0a","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4dd7a53f1c5b44693c26dac4b9b5bd5bb9d604c8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7230cc456d4bb2221c20c5f1d22b38b8576aa16f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ae36a5b609ae79f4de966328b78d2584be9719a4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/fe602c91a52e161ace4afd5bdb8f33270c554c6f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-10-06T08:50:17.392Z","slug":"CVE-2026-98366","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: validate access flags before swapping the MR's PD\n\nrxe_rereg_user_mr() reassigns mr->ibmr.pd first and only then\nvalidates the IB_MR_REREG_ACCESS argument:\n\n\tif (flags & IB_MR_REREG_PD) {\n\t\trxe_put(old_pd);\n\t\trxe_get(pd);\n\t\tmr->ibmr.pd = ibpd;\n\t}\n\n\tif (flags & IB_MR_REREG_ACCESS) {\n\t\tif (access & ~RXE_ACCESS_SUPPORTED_MR)\n\t\t\treturn ERR_PTR(-EOPNOTSUPP);\n\t\tmr->access = access;\n\t}\n\nBoth flags pass the entry check because RXE_MR_REREG_SUPPORTED is\nIB_MR_REREG_PD | IB_MR_REREG_ACCESS, so a caller can reach the access\ncheck with mr->ibmr.pd already reassigned.\n\nmr->ibmr.pd is owned by the core, which adjusts pd->usecnt only on the\nsuccess path: ib_uverbs_rereg_mr() jumps to put_new_uobj on a driver error\nwithout undoing the reassignment, so mr->pd == new_pd while the usecnts\nstill charge the MR to orig_pd. ib_dereg_mr_user() then decrements\nnew_pd, whose count can reach zero while a memory window still references\nit; uverbs_free_pd() frees the PD on that count alone and rxe_mw_cleanup()\nwrites to freed memory:\n\n  BUG: KASAN: slab-use-after-free in __rxe_put+0x31/0xa0\n  Write of size 4 at addr ffff8881301dd690 by task rxe_poc/591\n   __rxe_put+0x31/0xa0\n   rxe_mw_cleanup+0x42/0x200\n   __rxe_cleanup+0x115/0x370\n   rxe_dealloc_mw+0x4c/0x80\n  Allocated by task 591:\n   ib_uverbs_alloc_pd+0x258/0x540\n  Freed by task 591:\n   ib_dealloc_pd_user+0x174/0x210\n   uverbs_free_pd+0x8d/0xc0\n   ib_uverbs_dealloc_pd+0x18e/0x1d0\n\nValidate the access flags before mutating any state so the callback either\napplies every requested change or none.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}