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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-98366

RDMA/rxe: validate access flags before swapping the MR's PD

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: RDMA/rxe: validate access flags before swapping the MR's PD rxe_rereg_user_mr() reassigns mr->ibmr.pd first and only then validates the IB_MR_REREG_ACCESS argument: if (flags & IB_MR_REREG_PD) { rxe_put(old_pd); rxe_get(pd); mr->ibmr.pd = ibpd; } if (flags & IB_MR_REREG_ACCESS) { if (access & ~RXE_ACCESS_SUPPORTED_MR) return ERR_PTR(-EOPNOTSUPP); mr->access = access; } Both flags pass the entry check because RXE_MR_REREG_SUPPORTED is IB_MR_REREG_PD | IB_MR_REREG_ACCESS, so a caller can reach the access check with mr->ibmr.pd already reassigned. mr->ibmr.pd is owned by the core, which adjusts pd->usecnt only on the success path: ib_uverbs_rereg_mr() jumps to put_new_uobj on a driver error without undoing the reassignment, so mr->pd == new_pd while the usecnts still charge the MR to orig_pd. ib_dereg_mr_user() then decrements new_pd, whose count can reach zero while a memory window still references it; uverbs_free_pd() frees the PD on that count alone and rxe_mw_cleanup() writes to freed memory: BUG: KASAN: slab-use-after-free in __rxe_put+0x31/0xa0 Write of size 4 at addr ffff8881301dd690 by task rxe_poc/591 __rxe_put+0x31/0xa0 rxe_mw_cleanup+0x42/0x200 __rxe_cleanup+0x115/0x370 rxe_dealloc_mw+0x4c/0x80 Allocated by task 591: ib_uverbs_alloc_pd+0x258/0x540 Freed by task 591: ib_dealloc_pd_user+0x174/0x210 uverbs_free_pd+0x8d/0xc0 ib_uverbs_dealloc_pd+0x18e/0x1d0 Validate the access flags before mutating any state so the callback either applies every requested change or none.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c to < 08f12745cb72981aa2cabe214af0c7a42a856f0aaffected
  • 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c to < 7230cc456d4bb2221c20c5f1d22b38b8576aa16faffected
  • 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c to < fe602c91a52e161ace4afd5bdb8f33270c554c6faffected
  • 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c to < 4dd7a53f1c5b44693c26dac4b9b5bd5bb9d604c8affected
  • 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c to < ae36a5b609ae79f4de966328b78d2584be9719a4affected

Linux Linux

Default version status: affected

  • 6.5affected
  • 0 to < 6.5unaffected
  • 6.6.158 to ≤ 6.6.*unaffected
  • 6.12.112 to ≤ 6.12.*unaffected
  • 6.18.54 to ≤ 6.18.*unaffected
  • 7.2.8 to ≤ 7.2.*unaffected
  • 7.3 to ≤ *unaffected

References