Siemens SIMATIC S7-1500 CPU 1518 MFP Improper Input Validation (CVE-2025-39845)

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

include('compat.inc');

if (description)
{
  script_id(505648);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/27");

  script_cve_id("CVE-2025-39845");

  script_name(english:"Siemens SIMATIC S7-1500 CPU 1518 MFP Improper Input Validation (CVE-2025-39845)");

  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:
x86/mm/64: define ARCH_PAGE_TABLE_SYNC_MASK and
arch_sync_kernel_mappings()    Define ARCH_PAGE_TABLE_SYNC_MASK and
arch_sync_kernel_mappings() to ensure  page tables are properly
synchronized when calling p*d_populate_kernel().    For 5-level
paging, synchronization is performed via  pgd_populate_kernel().  In
4-level paging, pgd_populate() is a no-op, so  synchronization is
instead performed at the P4D level via  p4d_populate_kernel().    This
fixes intermittent boot failures on systems using 4-level paging and
a large amount of persistent memory:      BUG: unable to handle page
fault for address: ffffe70000000034    #PF: supervisor write access in
kernel mode    #PF: error_code(0x0002) - not-present page    PGD 0 P4D
0    Oops: 0002 [#1] SMP NOPTI    RIP:
0010:__init_single_page+0x9/0x6d    Call Trace:     <TASK>
__init_zone_device_page+0x17/0x5d
memmap_init_zone_device+0x154/0x1bb     pagemap_range+0x2e0/0x40f
memremap_pages+0x10b/0x2f0     devm_memremap_pages+0x1e/0x60
dev_dax_probe+0xce/0x2ec [device_dax]     dax_bus_probe+0x6d/0xc9
[... snip ...]     </TASK>    It also fixes a crash in
vmemmap_set_pmd() caused by accessing vmemmap  before
sync_global_pgds() [1]:      BUG: unable to handle page fault for
address: ffffeb3ff1200000    #PF: supervisor write access in kernel
mode    #PF: error_code(0x0002) - not-present page    PGD 0 P4D 0
Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI    Tainted: [W]=WARN    RIP:
0010:vmemmap_set_pmd+0xff/0x230     <TASK>
vmemmap_populate_hugepages+0x176/0x180     vmemmap_populate+0x34/0x80
__populate_section_memmap+0x41/0x90     sparse_add_section+0x121/0x3e0
__add_pages+0xba/0x150     add_pages+0x1d/0x70
memremap_pages+0x3dc/0x810     devm_memremap_pages+0x1c/0x60
xe_devm_add+0x8b/0x100 [xe]     xe_tile_init_noalloc+0x6a/0x70 [xe]
xe_device_probe+0x48c/0x740 [xe]     [... snip ...]

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-019113.html");
  script_set_attribute(attribute:"see_also", value:"https://cert-portal.siemens.com/productcert/html/ssa-032379.html");
  script_set_attribute(attribute:"see_also", value:"https://support.industry.siemens.com/cs/ww/en/view/109814144/");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2025-39845");

  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:"2025/09/19");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/05/12");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/07/27");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:simatic_s7-1500_cpu_firmware:3.1.6");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:siplus_s7-1500_cpu_firmware");
  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_cpu_firmware:3.1.6" :
        {"versionStartIncluding" : "3.1.6", "family" : "S71500", "orderNumbers" : ['6ES7518-4FX00-1AC0', '6ES7518-4AX00-1AB0', '6ES7518-4AX00-1AC0', '6ES7518-4FX00-1AB0']},
    "cpe:/o:siemens:siplus_s7-1500_cpu_firmware" :
        {"family" : "S71500", "orderNumbers" : ['6AG1518-4AX00-4AC0']}
};

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