Siemens S7-1500 Use After Free (CVE-2025-39977)

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

include('compat.inc');

if (description)
{
  script_id(505089);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/02/11");

  script_cve_id("CVE-2025-39977");

  script_name(english:"Siemens S7-1500 Use After Free (CVE-2025-39977)");

  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:
futex: Prevent use-after-free during requeue-PI    syzbot managed to
trigger the following race:       T1                               T2
futex_wait_requeue_pi()     futex_do_wait()       schedule()
futex_requeue()
futex_proxy_trylock_atomic()
futex_requeue_pi_prepare()
requeue_pi_wake_futex()
futex_requeue_pi_complete()                                        /*
preempt */             * timeout/ signal wakes T1 *
futex_requeue_pi_wakeup_sync() // Q_REQUEUE_PI_LOCKED
futex_hash_put()    // back to userland, on stack futex_q is garbage
/* back */
wake_up_state(q->task, TASK_NORMAL);    In this scenario
futex_wait_requeue_pi() is able to leave without using
futex_q::lock_ptr for synchronization.    This can be prevented by
reading futex_q::task before updating the  futex_q::requeue_state. A
reference on the task_struct is not needed  because
requeue_pi_wake_futex() is invoked with a spinlock_t held which
implies a RCU read section.    Even if T1 terminates immediately
after, the task_struct will remain valid  during T2's wake_up_state().
A READ_ONCE on futex_q::task before  futex_requeue_pi_complete() is
enough because it ensures that the variable  is read before the state
is updated.    Read futex_q::task before updating the requeue state,
use it for the  following wakeup.

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-082556.html");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:H/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-2025-39977");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(416);

  script_set_attribute(attribute:"vuln_publication_date", value:"2025/06/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2025/06/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/02/10");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:simatic_s7-1500_cpu_firmware:3.1.5");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:siplus_s7-1500_cpu_firmware:3.1.5");
  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:3.1.5" :
        {"versionStartIncluding" : "3.1.5", "family" : "S71500", "orderNumbers" : ['6ES7518-4AX00-1AB0', '6ES7518-4FX00-1AC0', '6ES7518-4FX00-1AB0', '6ES7518-4AX00-1AC0']},
    "cpe:/o:siemens:siplus_s7-1500_cpu_firmware:3.1.5" :
        {"versionStartIncluding" : "3.1.5", "family" : "S71500", "orderNumbers" : ['6AG1518-4AX00-4AC0']}
};

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