CVE-2026-93224 (GCVE-0-2026-93224)

Vulnerability from cvelistv5 – Published: 2026-09-24 15:21 – Updated: 2026-09-25 05:09
VLAI
Title
svcrdma: Fix unmatched rn_unregister on failed accept
Summary
In the Linux kernel, the following vulnerability has been resolved: svcrdma: Fix unmatched rn_unregister on failed accept When svc_rdma_accept() takes the errout path before rpcrdma_rn_register() has succeeded, the existing cleanup block calls rpcrdma_rn_unregister(dev, &newxprt->sc_rn) unconditionally. svcxprt_rdma is kzalloc'd, so on that path sc_rn.rn_index is 0 and sc_rn.rn_done is NULL; the unregister therefore xa_erase()s another caller's slot 0 and performs an unmatched kref_put() on the rpcrdma_device's rd_kref. The same errout also brackets the cleanup with svc_xprt_get()/ svc_xprt_put() around the kref_init() birth reference. The kref goes 1 -> 2 -> 1 and never reaches 0, so the svcxprt_rdma (and the net/ns_tracker it pinned) is leaked on every failed accept. rpcrdma_rn_register() writes rn->rn_done last, only after xa_alloc() and kref_get() have both succeeded, so rn_done == NULL is a natural "never registered" sentinel. Guard rpcrdma_rn_unregister() with an early return when rn_done is NULL, and clear rn_done before the matching xa_erase() so a repeated unregister is also a no-op. With that guard in place, the accept errout drops the kref_init() birth reference via svc_xprt_put(), which dispatches svc_rdma_free(). Teardown of sc_qp, sc_sq_cq, sc_rq_cq, and sc_pd runs under existing IS_ERR/NULL guards in svc_rdma_free(); sc_rn is covered by the new rn_done sentinel; sc_cm_id is non-NULL on every errout path because svc_rdma_accept() dereferences it above the first goto errout. svc_xprt_free() drops the module reference associated with the freed transport, and svc_handle_xprt() drops its pre-acquired reference when ->xpo_accept() returns NULL. Take a replacement module reference before svc_xprt_put() so the two module_put()s remain balanced. The rn_done guard also covers svc_rdma_free()'s non-listener call to rpcrdma_rn_unregister() for transports whose register attempt failed or never ran.
Severity
8.1 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: cb3cba0ec372fa7c5f5f5c12990bef02e458ab86 , < 0335800071a6dfdf7d21d729b5e7d8fa98936211 (git)
Affected: 8ac6fcae5dc0e801f1c82a83f5ae2c0a4db19932 , < 5aabe070c00e5bdf4ab150fb5f72ad5f266d6241 (git)
Affected: 8ac6fcae5dc0e801f1c82a83f5ae2c0a4db19932 , < 45a444a17240f4fa2235f0dfd4a96fc80f1eb2c2 (git)
Affected: 8ac6fcae5dc0e801f1c82a83f5ae2c0a4db19932 , < 26190394c64c9429481fc88a4738f70bb92fb352 (git)
Affected: d310955106c358c8e1ea682defd8e21af44a6cba (git)
Affected: 6.12.35 , < 6.12.109 (semver)
Affected: 6.15.4 , < 6.16 (semver)
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Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.12.109 , ≤ 6.12.* (semver)
Unaffected: 6.18.50 , ≤ 6.18.* (semver)
Unaffected: 7.2.4 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Fix unmatched rn_unregister on failed accept\n\nWhen svc_rdma_accept() takes the errout path before\nrpcrdma_rn_register() has succeeded, the existing cleanup block\ncalls rpcrdma_rn_unregister(dev, \u0026newxprt-\u003esc_rn) unconditionally.\nsvcxprt_rdma is kzalloc\u0027d, so on that path sc_rn.rn_index is 0 and\nsc_rn.rn_done is NULL; the unregister therefore xa_erase()s another\ncaller\u0027s slot 0 and performs an unmatched kref_put() on the\nrpcrdma_device\u0027s rd_kref.\n\nThe same errout also brackets the cleanup with svc_xprt_get()/\nsvc_xprt_put() around the kref_init() birth reference. The kref\ngoes 1 -\u003e 2 -\u003e 1 and never reaches 0, so the svcxprt_rdma (and the\nnet/ns_tracker it pinned) is leaked on every failed accept.\n\nrpcrdma_rn_register() writes rn-\u003ern_done last, only after xa_alloc()\nand kref_get() have both succeeded, so rn_done == NULL is a natural\n\"never registered\" sentinel. Guard rpcrdma_rn_unregister() with an\nearly return when rn_done is NULL, and clear rn_done before the\nmatching xa_erase() so a repeated unregister is also a no-op.\n\nWith that guard in place, the accept errout drops the kref_init()\nbirth reference via svc_xprt_put(), which dispatches svc_rdma_free().\nTeardown of sc_qp, sc_sq_cq, sc_rq_cq, and sc_pd runs under existing\nIS_ERR/NULL guards in svc_rdma_free(); sc_rn is covered by the new\nrn_done sentinel; sc_cm_id is non-NULL on every errout path because\nsvc_rdma_accept() dereferences it above the first goto errout.\n\nsvc_xprt_free() drops the module reference associated with the freed\ntransport, and svc_handle_xprt() drops its pre-acquired reference\nwhen -\u003expo_accept() returns NULL. Take a replacement module reference\nbefore svc_xprt_put() so the two module_put()s remain balanced.\n\nThe rn_done guard also covers svc_rdma_free()\u0027s non-listener call\nto rpcrdma_rn_unregister() for transports whose register attempt\nfailed or never ran."
        }
      ],
      "metrics": [
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          "cvssV3_1": {
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - svcrdma is nfsd\u0027s RPC-over-RDMA server; a remote peer over routable RoCEv2 or iWARP sends RDMA_CM CONNECT_REQUEST to svc_rdma_listen_handler/handle_connect_req, which queues newxprt so svc_handle_xprt calls svc_rdma_accept, whose errout invokes the unguarded rpcrdma_rn_unregister.\nAC:H - The unmatched rpcrdma_rn_unregister in svc_rdma_accept errout runs only if rpcrdma_rn_register failed (RPCRDMA_RD_F_REMOVING or xa_alloc ENOMEM); a remote peer can send CONNECT_REQUEST but cannot unbind the IB device or force that GFP_KERNEL failure, and the UAF needs that in-progress rpcrdma_remove_one.\nPR:N - RDMA_CM CONNECT_REQUEST handling in svc_rdma_listen_handler, handle_connect_req, and svc_rdma_accept runs before svc_process/svc_authenticate; the CM handshake has no RPC or NFS credential check, so an unauthenticated peer can drive the failed-accept errout.\nUI:N - Sending CONNECT_REQUEST to an NFS/RDMA listener already created via nfsd portlist is enough to reach svc_rdma_accept; racing ib_unregister_device is attack complexity, not a victim mount, click, or other user action.\nS:U - The wrong-slot rd_xa erase, unmatched rd_kref put, and any use-after-free of rpcrdma_device or the victim svcxprt_rdma\u0027s IB objects stay in the host kernel that runs nfsd/svcrdma; this is not a VM, IOMMU, or sandbox escape.\nC:H - On pre-register errout, rpcrdma_rn_unregister xa_erase()s rd_xa index 0 (kzalloc\u0027d sc_rn.rn_index) of another transport and kref_put()s rd_kref while rpcrdma_remove_one may walk the same xarray; that transport\u0027s sc_cm_id/QP and the kfree\u0027d rpcrdma_device become reclaimable slab UAF reads.\nI:H - The extra kref_put can make rpcrdma_remove_one\u0027s refcount_dec_and_test skip wait_for_completion and kfree(rd) while a live transport later xa_erase/kref_put or QP/CM ops write through the freed rpcrdma_device or un-notified IB objects, a UAF write primitive.\nA:H - A concurrent rpcrdma_remove_one that proceeds after the unmatched kref_put, or later QP/CM use of a transport whose slot-0 notification was erased, dereferences freed IB or rpcrdma_device memory and oopses or panics; any UAF is availability High per kernel CVSS guidance."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-25T05:09:45.728Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0335800071a6dfdf7d21d729b5e7d8fa98936211"
        },
        {
          "url": "https://git.kernel.org/stable/c/5aabe070c00e5bdf4ab150fb5f72ad5f266d6241"
        },
        {
          "url": "https://git.kernel.org/stable/c/45a444a17240f4fa2235f0dfd4a96fc80f1eb2c2"
        },
        {
          "url": "https://git.kernel.org/stable/c/26190394c64c9429481fc88a4738f70bb92fb352"
        }
      ],
      "title": "svcrdma: Fix unmatched rn_unregister on failed accept",
      "x_generator": {
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93224",
    "datePublished": "2026-09-24T15:21:10.542Z",
    "dateReserved": "2026-09-17T16:02:15.094Z",
    "dateUpdated": "2026-09-25T05:09:45.728Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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    "epss": {
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      "date": "2026-09-25",
      "epss": "0.00453",
      "percentile": "0.36727"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "net/sunrpc/xprtrdma/ib_client.c",
                  "net/sunrpc/xprtrdma/svc_rdma_transport.c"
                ],
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                "product": "Linux",
                "programFiles": [
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                "vendor": "Linux",
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                    "lessThanOrEqual": "6.18.*",
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                    "status": "unaffected",
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                    "versionType": "original_commit_for_fix"
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              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsvcrdma: Fix unmatched rn_unregister on failed accept\n\nWhen svc_rdma_accept() takes the errout path before\nrpcrdma_rn_register() has succeeded, the existing cleanup block\ncalls rpcrdma_rn_unregister(dev, \u0026newxprt-\u003esc_rn) unconditionally.\nsvcxprt_rdma is kzalloc\u0027d, so on that path sc_rn.rn_index is 0 and\nsc_rn.rn_done is NULL; the unregister therefore xa_erase()s another\ncaller\u0027s slot 0 and performs an unmatched kref_put() on the\nrpcrdma_device\u0027s rd_kref.\n\nThe same errout also brackets the cleanup with svc_xprt_get()/\nsvc_xprt_put() around the kref_init() birth reference. The kref\ngoes 1 -\u003e 2 -\u003e 1 and never reaches 0, so the svcxprt_rdma (and the\nnet/ns_tracker it pinned) is leaked on every failed accept.\n\nrpcrdma_rn_register() writes rn-\u003ern_done last, only after xa_alloc()\nand kref_get() have both succeeded, so rn_done == NULL is a natural\n\"never registered\" sentinel. Guard rpcrdma_rn_unregister() with an\nearly return when rn_done is NULL, and clear rn_done before the\nmatching xa_erase() so a repeated unregister is also a no-op.\n\nWith that guard in place, the accept errout drops the kref_init()\nbirth reference via svc_xprt_put(), which dispatches svc_rdma_free().\nTeardown of sc_qp, sc_sq_cq, sc_rq_cq, and sc_pd runs under existing\nIS_ERR/NULL guards in svc_rdma_free(); sc_rn is covered by the new\nrn_done sentinel; sc_cm_id is non-NULL on every errout path because\nsvc_rdma_accept() dereferences it above the first goto errout.\n\nsvc_xprt_free() drops the module reference associated with the freed\ntransport, and svc_handle_xprt() drops its pre-acquired reference\nwhen -\u003expo_accept() returns NULL. Take a replacement module reference\nbefore svc_xprt_put() so the two module_put()s remain balanced.\n\nThe rn_done guard also covers svc_rdma_free()\u0027s non-listener call\nto rpcrdma_rn_unregister() for transports whose register attempt\nfailed or never ran."
          }
        ],
        "id": "CVE-2026-93224",
        "lastModified": "2026-09-25T05:17:00.290",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "HIGH",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 8.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 2.2,
              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-24T16:17:17.720",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/0335800071a6dfdf7d21d729b5e7d8fa98936211"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/26190394c64c9429481fc88a4738f70bb92fb352"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/45a444a17240f4fa2235f0dfd4a96fc80f1eb2c2"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/5aabe070c00e5bdf4ab150fb5f72ad5f266d6241"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-25T23:50:28Z",
      "cve": "CVE-2026-93224",
      "id": "CVE-2026-93224",
      "initial_release_date": "2026-09-24T23:49:42Z",
      "product_status:known_not_affected": "347",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-93224",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-93224.json",
      "version": "3"
    }
  }
}



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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.