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CVE-2026-98366

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

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.

Timeline

  1. ID reserved

    By Linux

  2. · 11 days later

    Published

  3. · 13 days later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2026-98366, by who scored it
Scored byCVSSScoreVector
LinuxCNA (assigner)3.1High7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Received3.1High7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
0.12% · top 98% of all CVEs (10 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.

Affected products

  • Linux · Linux

    • affected 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c – < 08f12745cb72981aa2cabe214af0c7a42a856f0a
    • affected 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c – < 7230cc456d4bb2221c20c5f1d22b38b8576aa16f
    • affected 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c – < fe602c91a52e161ace4afd5bdb8f33270c554c6f
    • affected 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c – < 4dd7a53f1c5b44693c26dac4b9b5bd5bb9d604c8
    • affected 544c7f62cf32db2bd358f1e8a40a98bf98fa2a5c – < ae36a5b609ae79f4de966328b78d2584be9719a4
  • Linux · Linux

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

References

5

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .