Siemens SIMATIC S7-1500 TM MFP Improper Input Validation (CVE-2026-31630)

#%NASL_MIN_LEVEL 80900
##
# (C) Tenable, Inc.
##

include('compat.inc');

if (description)
{
  script_id(506439);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/10/21");

  script_cve_id("CVE-2026-31630");

  script_name(english:"Siemens SIMATIC S7-1500 TM MFP Improper Input Validation (CVE-2026-31630)");

  script_set_attribute(attribute:"synopsis", value:
"The remote OT asset is affected by a vulnerability.");
  script_set_attribute(attribute:"description", value:
"In the Linux kernel, the following vulnerability has been resolved:

rxrpc: proc: size address buffers for %pISpc output

The AF_RXRPC procfs helpers format local and remote socket addresses into
fixed 50-byte stack buffers with '%pISpc'.

That is too small for the longest current-tree IPv6-with-port form the
formatter can produce. In lib/vsprintf.c, the compressed IPv6 path uses a
dotted-quad tail not only for v4mapped addresses, but also for ISATAP
addresses via ipv6_addr_is_isatap().

As a result, a case such as

  [ffff:ffff:ffff:ffff:0:5efe:255.255.255.255]:65535

is possible with the current formatter. That is 50 visible characters, so
51 bytes including the trailing NUL, which does not fit in the existing
char[50] buffers used by net/rxrpc/proc.c.

Size the buffers from the formatter's maximum textual form and switch the
call sites to scnprintf().

Changes since v1:
- correct the changelog to cite the actual maximum current-tree case
  explicitly
- frame the proof around the ISATAP formatting path instead of the earlier
  mapped-v4 example

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.");
  script_set_attribute(attribute:"see_also", value:"https://cert-portal.siemens.com/productcert/html/ssa-784472.html");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-31630");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(20);

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/10/13");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/10/13");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/10/20");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:simatic_s7-1500_tm_mfp");
  script_set_attribute(attribute:"generated_plugin", value:"former");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Tenable.ot");

  script_copyright(english:"This script is Copyright (C) 2026 and is owned by Tenable, Inc. or an Affiliate thereof.");

  script_dependencies("tenable_ot_api_integration.nasl");
  script_require_keys("Tenable.ot/Siemens");

  exit(0);
}


include('tenable_ot_cve_funcs.inc');

get_kb_item_or_exit('Tenable.ot/Siemens');

var asset = tenable_ot::assets::get(vendor:'Siemens');

var vuln_cpes = {
    "cpe:/o:siemens:simatic_s7-1500_tm_mfp" :
        {"versionEndIncluding" : "1.1.1", "versionStartIncluding" : "1.1.1", "family" : "S71500", "orderNumbers": ["6ES7558-1AA00-0AB0"]}
};

tenable_ot::cve::compare_and_report(asset:asset, cpes:vuln_cpes, severity:SECURITY_WARNING);