CVE-2026-89700 (GCVE-0-2026-89700)
Vulnerability from cvelistv5
Published
2026-09-11 19:46
Modified
2026-10-19 08:51
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: validate sockaddr length per family in listener_set nfsd_sock_nl_policy declares NFSD_A_SOCK_ADDR as a bare NLA_BINARY attribute with no minimum length. A CAP_NET_ADMIN caller can send a 16-byte NFSD_A_SOCK_ADDR with sa_family=AF_INET6, causing a 12-byte OOB read across three consumers (rpc_cmp_addr_port, svc_find_listener, kernel_bind). nfsd_nl_listener_set_doit() also parsed and validated each listener entry inline in two separate loops, interleaved with mutating the running listener configuration. The validation was duplicated, used an open-coded "nla_len < sizeof(struct sockaddr)" check that was too short for AF_INET6, and handled a malformed entry inconsistently depending on which loop noticed it. Add an nfsd_nl_validate_listeners() helper that walks the entire list once and confirms each entry parses, carries both an address and a transport name, and is long enough for its address family (sizeof(struct sockaddr_in) for AF_INET, sizeof(struct sockaddr_in6) for AF_INET6, -EAFNOSUPPORT otherwise). Call it before taking nfsd_mutex or creating the serv, so a malformed request fails cleanly with no side effects. Since every entry is known valid by the time the two existing loops run, drop the redundant presence and per-family length checks from both, leaving only the nla_parse_nested() call needed to extract the data.
References
Impacted products
Vendor Product Version
Linux Linux Version: 16a471177496c8e04a9793812c187a2c1a2192fa
Version: 16a471177496c8e04a9793812c187a2c1a2192fa
Version: 16a471177496c8e04a9793812c187a2c1a2192fa
Version: 16a471177496c8e04a9793812c187a2c1a2192fa
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{
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          "product": "Linux",
          "programFiles": [
            "fs/nfsd/nfsctl.c"
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: validate sockaddr length per family in listener_set\n\nnfsd_sock_nl_policy declares NFSD_A_SOCK_ADDR as a bare NLA_BINARY\nattribute with no minimum length. A CAP_NET_ADMIN caller can send a\n16-byte NFSD_A_SOCK_ADDR with sa_family=AF_INET6, causing a 12-byte\nOOB read across three consumers (rpc_cmp_addr_port, svc_find_listener,\nkernel_bind).\n\nnfsd_nl_listener_set_doit() also parsed and validated each listener\nentry inline in two separate loops, interleaved with mutating the\nrunning listener configuration. The validation was duplicated, used an\nopen-coded \"nla_len \u003c sizeof(struct sockaddr)\" check that was too short\nfor AF_INET6, and handled a malformed entry inconsistently depending on\nwhich loop noticed it.\n\nAdd an nfsd_nl_validate_listeners() helper that walks the entire list\nonce and confirms each entry parses, carries both an address and a\ntransport name, and is long enough for its address family\n(sizeof(struct sockaddr_in) for AF_INET, sizeof(struct sockaddr_in6)\nfor AF_INET6, -EAFNOSUPPORT otherwise). Call it before taking\nnfsd_mutex or creating the serv, so a malformed request fails cleanly\nwith no side effects.\n\nSince every entry is known valid by the time the two existing loops\nrun, drop the redundant presence and per-family length checks from\nboth, leaving only the nla_parse_nested() call needed to extract the\ndata."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:51:13.379Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/bf85a0f1e45258f90ceeec14772b5769697dfd75"
        },
        {
          "url": "https://git.kernel.org/stable/c/2aca70c18c5f5d06004122861fb151d5fcc57faf"
        },
        {
          "url": "https://git.kernel.org/stable/c/22d0e4752ca88fd84196d22ebeedc905e6540440"
        },
        {
          "url": "https://git.kernel.org/stable/c/bdcc85c2b05a9378d8bd2d65f9fc41440a3cf464"
        }
      ],
      "title": "nfsd: validate sockaddr length per family in listener_set",
      "x_generator": {
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      }
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89700",
    "datePublished": "2026-09-11T19:46:18.076Z",
    "dateReserved": "2026-09-11T19:38:34.750Z",
    "dateUpdated": "2026-10-19T08:51:13.379Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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