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CVE-2026-89784

Status: ReceivedUnscored—

In the Linux kernel, the following vulnerability has been resolved:

SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6

rpcb_register_inet4() and rpcb_register_inet6() store the result of rpc_sockaddr2uaddr() into map->r_addr without checking it for NULL. rpc_sockaddr2uaddr() returns NULL when its final kstrdup() fails, and the unchecked NULL is then carried into the synchronous RPCBPROC_SET encode path: rpcb_register_call() -> rpc_call_sync() -> rpcb_enc_getaddr() -> encode_rpcb_string(), whose first statement is strlen(string), dereferencing NULL and oopsing the kernel.

The crash reproduces under failslab on v6.12; with KASAN the NULL dereference surfaces as a fault on the shadow of address zero:

Read full descriptionShow less

The crash is reachable when an in-kernel RPC service (nfsd, lockd, nfs-callback) registers with the local rpcbind under enough memory pressure for the small GFP_KERNEL kstrdup() in rpc_sockaddr2uaddr() to fail. The asynchronous getport path already handles this exact failure mode by returning -ENOMEM; only the two register helpers omit the check.

Mirror that handling: bail out with -ENOMEM when rpc_sockaddr2uaddr() returns NULL, before the address is fed into the encoder.

Technical details traces, logs and code from the original report
 Oops: general protection fault, probably for non-canonical address
       0xdffffc0000000000 [#1] PREEMPT SMP KASAN
 RIP: 0010:strlen (lib/string.c:409)
 Call Trace:
  encode_rpcb_string (net/sunrpc/rpcb_clnt.c:890)
  rpcb_enc_getaddr (net/sunrpc/rpcb_clnt.c:910)
  rpcauth_wrap_req_encode (net/sunrpc/auth.c:745)
  call_encode (net/sunrpc/clnt.c:1966)
  __rpc_execute (net/sunrpc/sched.c:952)
  rpc_run_task (net/sunrpc/clnt.c:1243)
  rpc_call_sync (net/sunrpc/clnt.c:1272)
  rpcb_v4_register (net/sunrpc/rpcb_clnt.c:500)
  svc_generic_rpcbind_set
  nfsd_rpcbind_set
  svc_register
  svc_setup_socket
  svc_addsock
  write_ports
  nfsctl_transaction_write
  vfs_write

CVSS

NVD hasn't assigned a CVSS score to this CVE (common since the April 2026 policy change).

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux KernelAI

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-89784",
  "cveTags": [],
  "metrics": {},
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "d77385f23830ee6c400569bac8b37e6eb3b7d360",
              "lessThan": "04441b792ec40eb66349b5fab34b6a2090b5b2dd",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d77385f23830ee6c400569bac8b37e6eb3b7d360",
              "lessThan": "5a51c49ddb37b883566874aecc66bc5a2e617a96",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d77385f23830ee6c400569bac8b37e6eb3b7d360",
              "lessThan": "4a6095de8cb1858e05bdf70b3e7d6d7645c25041",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d77385f23830ee6c400569bac8b37e6eb3b7d360",
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              "versionType": "git"
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            {
              "status": "affected",
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              "lessThan": "4e01022974355732e748ec8ebc97c558cb624ffe",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "d77385f23830ee6c400569bac8b37e6eb3b7d360",
              "lessThan": "cda4aacfb0bbf5c0f90fd0b42c72c749635d1368",
              "versionType": "git"
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            {
              "status": "affected",
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              "versionType": "git"
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            {
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              "lessThan": "fd22370226a0d8109045d0831fd5aaadee921693",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "net/sunrpc/rpcb_clnt.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "3.2"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "3.2",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver",
              "lessThanOrEqual": "6.6.*"
            },
            {
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver",
              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
            {
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver",
              "lessThanOrEqual": "7.2.*"
            },
            {
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "net/sunrpc/rpcb_clnt.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2026-09-16T09:17:09.060",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/04441b792ec40eb66349b5fab34b6a2090b5b2dd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/12bf3e0182ccdaf3b412756a756d3944a7dacaa9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4a6095de8cb1858e05bdf70b3e7d6d7645c25041",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4e01022974355732e748ec8ebc97c558cb624ffe",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/5a51c49ddb37b883566874aecc66bc5a2e617a96",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cda4aacfb0bbf5c0f90fd0b42c72c749635d1368",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/eb476289c12cc22c8766f8a84eeb7ab46c4e8fb6",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/fd22370226a0d8109045d0831fd5aaadee921693",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Received",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6\n\nrpcb_register_inet4() and rpcb_register_inet6() store the result of\nrpc_sockaddr2uaddr() into map->r_addr without checking it for NULL.\nrpc_sockaddr2uaddr() returns NULL when its final kstrdup() fails, and\nthe unchecked NULL is then carried into the synchronous RPCBPROC_SET\nencode path: rpcb_register_call() -> rpc_call_sync() ->\nrpcb_enc_getaddr() -> encode_rpcb_string(), whose first statement is\nstrlen(string), dereferencing NULL and oopsing the kernel.\n\nThe crash reproduces under failslab on v6.12; with KASAN the NULL\ndereference surfaces as a fault on the shadow of address zero:\n\n Oops: general protection fault, probably for non-canonical address\n       0xdffffc0000000000 [#1] PREEMPT SMP KASAN\n RIP: 0010:strlen (lib/string.c:409)\n Call Trace:\n  encode_rpcb_string (net/sunrpc/rpcb_clnt.c:890)\n  rpcb_enc_getaddr (net/sunrpc/rpcb_clnt.c:910)\n  rpcauth_wrap_req_encode (net/sunrpc/auth.c:745)\n  call_encode (net/sunrpc/clnt.c:1966)\n  __rpc_execute (net/sunrpc/sched.c:952)\n  rpc_run_task (net/sunrpc/clnt.c:1243)\n  rpc_call_sync (net/sunrpc/clnt.c:1272)\n  rpcb_v4_register (net/sunrpc/rpcb_clnt.c:500)\n  svc_generic_rpcbind_set\n  nfsd_rpcbind_set\n  svc_register\n  svc_setup_socket\n  svc_addsock\n  write_ports\n  nfsctl_transaction_write\n  vfs_write\n\nThe crash is reachable when an in-kernel RPC service (nfsd, lockd,\nnfs-callback) registers with the local rpcbind under enough memory\npressure for the small GFP_KERNEL kstrdup() in rpc_sockaddr2uaddr() to\nfail. The asynchronous getport path already handles this exact failure\nmode by returning -ENOMEM; only the two register helpers omit the check.\n\nMirror that handling: bail out with -ENOMEM when rpc_sockaddr2uaddr()\nreturns NULL, before the address is fed into the encoder."
    }
  ],
  "lastModified": "2026-09-16T09:17:09.060",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}