Siemens RUGGEDCOM RST2428P Active Debug Code (CVE-2026-22977)

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

include('compat.inc');

if (description)
{
  script_id(505385);
  script_version("1.3");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/07/17");

  script_cve_id("CVE-2026-22977");
  script_xref(name:"ICSA", value:"26-188-05");

  script_name(english:"Siemens RUGGEDCOM RST2428P Active Debug Code (CVE-2026-22977)");

  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:
net: sock: fix hardened usercopy panic in sock_recv_errqueue
skbuff_fclone_cache was created without defining a usercopy region,
[1] unlike skbuff_head_cache which properly whitelists the cb[] field.
[2] This causes a usercopy BUG() when CONFIG_HARDENED_USERCOPY is
enabled and the kernel attempts to copy sk_buff.cb data to userspace
via sock_recv_errqueue() -> put_cmsg().    The crash occurs when: 1.
TCP allocates an skb using alloc_skb_fclone()     (from
skbuff_fclone_cache) [1]  2. The skb is cloned via skb_clone() using
the pre-allocated fclone  [3] 3. The cloned skb is queued to
sk_error_queue for timestamp  reporting 4. Userspace reads the error
queue via recvmsg(MSG_ERRQUEUE)  5. sock_recv_errqueue() calls
put_cmsg() to copy serr->ee from skb->cb  [4] 6. __check_heap_object()
fails because skbuff_fclone_cache has no     usercopy whitelist [5]
When cloned skbs allocated from skbuff_fclone_cache are used in the
socket error queue, accessing the sock_exterr_skb structure in skb->cb
via put_cmsg() triggers a usercopy hardening violation:    [
5.379589] usercopy: Kernel memory exposure attempt detected from SLUB
object 'skbuff_fclone_cache' (offset 296, size 16)!  [    5.382796]
kernel BUG at mm/usercopy.c:102!  [    5.383923] Oops: invalid opcode:
0000 [#1] SMP KASAN NOPTI  [    5.384903] CPU: 1 UID: 0 PID: 138 Comm:
poc_put_cmsg Not tainted 6.12.57 #7  [    5.384903] Hardware name:
QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014  [
5.384903] RIP: 0010:usercopy_abort+0x6c/0x80  [    5.384903] Code: 1a
86 51 48 c7 c2 40 15 1a 86 41 52 48 c7 c7 c0 15 1a 86 48 0f 45 d6 48
c7 c6 80 15 1a 86 48 89 c1 49 0f 45 f3 e8 84 27 88 ff <0f> 0b 490  [
5.384903] RSP: 0018:ffffc900006f77a8 EFLAGS: 00010246  [    5.384903]
RAX: 000000000000006f RBX: ffff88800f0ad2a8 RCX: 1ffffffff0f72e74  [
5.384903] RDX: 0000000000000000 RSI: 0000000000000004 RDI:
ffffffff87b973a0  [    5.384903] RBP: 0000000000000010 R08:
0000000000000000 R09: fffffbfff0f72e74  [    5.384903] R10:
0000000000000003 R11: 79706f6372657375 R12: 0000000000000001  [
5.384903] R13: ffff88800f0ad2b8 R14: ffffea00003c2b40 R15:
ffffea00003c2b00  [    5.384903] FS:  0000000011bc4380(0000)
GS:ffff8880bf100000(0000) knlGS:0000000000000000  [    5.384903] CS:
0010 DS: 0000 ES: 0000 CR0: 0000000080050033  [    5.384903] CR2:
000056aa3b8e5fe4 CR3: 000000000ea26004 CR4: 0000000000770ef0  [
5.384903] PKRU: 55555554  [    5.384903] Call Trace:  [    5.384903]
<TASK>  [    5.384903]  __check_heap_object+0x9a/0xd0  [    5.384903]
__check_object_size+0x46c/0x690  [    5.384903]  put_cmsg+0x129/0x5e0
[    5.384903]  sock_recv_errqueue+0x22f/0x380  [    5.384903]
tls_sw_recvmsg+0x7ed/0x1960  [    5.384903]  ?
srso_alias_return_thunk+0x5/0xfbef5  [    5.384903]  ?
schedule+0x6d/0x270  [    5.384903]  ?
srso_alias_return_thunk+0x5/0xfbef5  [    5.384903]  ?
mutex_unlock+0x81/0xd0  [    5.384903]  ? __pfx_mutex_unlock+0x10/0x10
[    5.384903]  ? __pfx_tls_sw_recvmsg+0x10/0x10  [    5.384903]  ?
_raw_spin_lock_irqsave+0x8f/0xf0  [    5.384903]  ?
_raw_read_unlock_irqrestore+0x20/0x40  [    5.384903]  ?
srso_alias_return_thunk+0x5/0xfbef5    The crash offset 296
corresponds to skb2->cb within skbuff_fclones:    - sizeof(struct
sk_buff) = 232 - offsetof(struct sk_buff, cb) = 40 -    offset of
skb2.cb in fclones = 232 + 40 = 272 - crash offset 296 =    272 + 24
(inside sock_exterr_skb.ee)    This patch uses a local stack variable
as a bounce buffer to avoid the hardened usercopy check failure.
[1]
https://elixir.bootlin.com/linux/v6.12.62/source/net/ipv4/tcp.c#L885
[2] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/skbuff.c
#L5104  [3] https://elixir.bootlin.com/linux/v6.12.62/source/net/core/
skbuff.c#L5566  [4] https://elixir.bootlin.com/linux/v6.12.62/source/n
et/core/skbuff.c#L5491  [5]
https://elixir.bootlin.com/linux/v6.12.62/source/mm/slub.c#L5719

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-253495.html");
  script_set_attribute(attribute:"see_also", value:"https://support.industry.siemens.com/cs/ww/en/view/110002573/");
  script_set_attribute(attribute:"see_also", value:"https://www.cisa.gov/news-events/ics-advisories/ICSA-26-188-05");
  script_set_attribute(attribute:"solution", value:
"Refer to the vendor advisory.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:N/I:N/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:N/I:N/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-2026-22977");

  script_set_attribute(attribute:"exploitability_ease", value:"No known exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"false");
  script_cwe_id(489);

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/01/21");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/02");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/18");

  script_set_attribute(attribute:"plugin_type", value:"remote");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:siemens:ruggedcom_rst2428p_firmware");
  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:ruggedcom_rst2428p_firmware" :
        {"family" : "RuggedCom", "orderNumbers" : ['6GK6242-6PA00'], "versionEndExcluding" : "4.0"}
};

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