Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098968)

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

include('compat.inc');

if (description)
{
  script_id(340341);
  script_version("1.2");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/08/28");

  script_cve_id("CVE-2025-21858");

  script_name(english:"Unity Linux 20.1050a Security Update: kernel (UTSA-2026-098968)");

  script_set_attribute(attribute:"synopsis", value:
"The Unity Linux host is missing one or more security updates.");
  script_set_attribute(attribute:"description", value:
"The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the
UTSA-2026-098968 advisory.

    In the Linux kernel, the following vulnerability has been resolved:

    geneve: Fix use-after-free in geneve_find_dev().

    syzkaller reported a use-after-free in geneve_find_dev() [0]
    without repro.

    geneve_configure() links struct geneve_dev.next to
    net_generic(net, geneve_net_id)->geneve_list.

    The net here could differ from dev_net(dev) if IFLA_NET_NS_PID,
    IFLA_NET_NS_FD, or IFLA_TARGET_NETNSID is set.

    When dev_net(dev) is dismantled, geneve_exit_batch_rtnl() finally
    calls unregister_netdevice_queue() for each dev in the netns,
    and later the dev is freed.

    However, its geneve_dev.next is still linked to the backend UDP
    socket netns.

    Then, use-after-free will occur when another geneve dev is created
    in the netns.

    Let's call geneve_dellink() instead in geneve_destroy_tunnels().

    [0]:
    BUG: KASAN: slab-use-after-free in geneve_find_dev drivers/net/geneve.c:1295 [inline]
    BUG: KASAN: slab-use-after-free in geneve_configure+0x234/0x858 drivers/net/geneve.c:1343
    Read of size 2 at addr ffff000054d6ee24 by task syz.1.4029/13441

    CPU: 1 UID: 0 PID: 13441 Comm: syz.1.4029 Not tainted 6.13.0-g0ad9617c78ac #24
    dc35ca22c79fb82e8e7bc5c9c9adafea898b1e3d
    Hardware name: linux,dummy-virt (DT)
    Call trace:
     show_stack+0x38/0x50 arch/arm64/kernel/stacktrace.c:466 (C)
     __dump_stack lib/dump_stack.c:94 [inline]
     dump_stack_lvl+0xbc/0x108 lib/dump_stack.c:120
     print_address_description mm/kasan/report.c:378 [inline]
     print_report+0x16c/0x6f0 mm/kasan/report.c:489
     kasan_report+0xc0/0x120 mm/kasan/report.c:602
     __asan_report_load2_noabort+0x20/0x30 mm/kasan/report_generic.c:379
     geneve_find_dev drivers/net/geneve.c:1295 [inline]
     geneve_configure+0x234/0x858 drivers/net/geneve.c:1343
     geneve_newlink+0xb8/0x128 drivers/net/geneve.c:1634
     rtnl_newlink_create+0x23c/0x868 net/core/rtnetlink.c:3795
     __rtnl_newlink net/core/rtnetlink.c:3906 [inline]
     rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021
     rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911
     netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543
     rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938
     netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
     netlink_unicast+0x618/0x838 net/netlink/af_netlink.c:1348
     netlink_sendmsg+0x5fc/0x8b0 net/netlink/af_netlink.c:1892
     sock_sendmsg_nosec net/socket.c:713 [inline]
     __sock_sendmsg net/socket.c:728 [inline]
     ____sys_sendmsg+0x410/0x6f8 net/socket.c:2568
     ___sys_sendmsg+0x178/0x1d8 net/socket.c:2622
     __sys_sendmsg net/socket.c:2654 [inline]
     __do_sys_sendmsg net/socket.c:2659 [inline]
     __se_sys_sendmsg net/socket.c:2657 [inline]
     __arm64_sys_sendmsg+0x12c/0x1c8 net/socket.c:2657
     __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
     invoke_syscall+0x90/0x278 arch/arm64/kernel/syscall.c:49
     el0_svc_common+0x13c/0x250 arch/arm64/kernel/syscall.c:132
     do_el0_svc+0x54/0x70 arch/arm64/kernel/syscall.c:151
     el0_svc+0x4c/0xa8 arch/arm64/kernel/entry-common.c:744
     el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:762
     el0t_64_sync+0x198/0x1a0 arch/arm64/kernel/entry.S:600

    Allocated by task 13247:
     kasan_save_stack mm/kasan/common.c:47 [inline]
     kasan_save_track+0x30/0x68 mm/kasan/common.c:68
     kasan_save_alloc_info+0x44/0x58 mm/kasan/generic.c:568
     poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
     __kasan_kmalloc+0x84/0xa0 mm/kasan/common.c:394
     kasan_kmalloc include/linux/kasan.h:260 [inline]
     __do_kmalloc_node mm/slub.c:4298 [inline]
     __kmalloc_node_noprof+0x2a0/0x560 mm/slub.c:4304
     __kvmalloc_node_noprof+0x9c/0x230 mm/util.c:645
     alloc_netdev_mqs+0xb8/0x11a0 net/core/dev.c:11470
     rtnl_create_link+0x2b8/0xb50 net/core/rtnetlink.c:3604
     rtnl_newlink_create+0x19c/0x868 net/core/rtnetlink.c:3780
     __rtnl_newlink net/core/rtnetlink.c:3906 [inline]
     rtnl_newlink+0x1054/0x1630 net/core/rtnetlink.c:4021
     rtnetlink_rcv_msg+0x61c/0x918 net/core/rtnetlink.c:6911
     netlink_rcv_skb+0x1dc/0x398 net/netlink/af_netlink.c:2543
     rtnetlink_rcv+0x34/0x50 net/core/rtnetlink.c:6938
     netlink_unicast_kernel net/netlink/af_n
    ---truncated---

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version
number.");
  # https://src.uniontech.com/#/security_advisory_detail?utsa_id=UTSA-2026-098968
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?2c008d5c");
  # https://lore.kernel.org/linux-cve-announce/2025031215-CVE-2025-21858-3986@gregkh
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?dbac4d98");
  script_set_attribute(attribute:"see_also", value:"https://nvd.nist.gov/vuln/detail/CVE-2025-21858");
  script_set_attribute(attribute:"solution", value:
"Update the affected kernel package.");
  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-2025-21858");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2024/04/09");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/08/10");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/08/26");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Unity Linux Local Security Checks");

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

  script_dependencies("ssh_get_info2.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/UOS-Server/release", "Host/UOS-Server/rpm-list", "Host/cpu");

  exit(0);
}
include('rpm2.inc');

if (!get_kb_item('Host/local_checks_enabled')) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
var os_product = get_kb_item('installed_os/local/SSH/0/product');
if (isnull(os_product) || 'UOS Server' >!< os_product) audit(AUDIT_OS_NOT, 'UOS Server');
var os_version = get_kb_item('installed_os/local/SSH/0/version');
if (isnull(os_version)) audit(AUDIT_UNKNOWN_APP_VER, 'UOS Server');
if (! preg(pattern:"^(20.1050a)([^0-9]|$)", string:os_version)) audit(AUDIT_OS_NOT, 'UOS Server 20.1050a', 'UOS Server ' + os_version);

if (!get_kb_item('Host/UOS-Server/rpm-list')) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item('Host/cpu');
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ('aarch64' >!< cpu && 'amd64' >!< cpu && 'loongarch64' >!< cpu && 'x86_64' >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, 'UOS Server', cpu);


var constraints = [
  {
    'release': '20',
    'sp': '1050a',
    'pkgs': [
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'aarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'amd64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'loongarch64', 'rpm_spec_vers_cmp':TRUE},
      {'reference':'kernel-4.19.0-91.82.132.24.uelc20', 'sp':'1050a', 'cpu':'x86_64', 'rpm_spec_vers_cmp':TRUE}
    ]
  }
];

var os_release = get_one_kb_item('installed_os/local/SSH/0/release');
var os_sp = get_one_kb_item('Host/*/minor_release');

var flag = 0;
var reference;
var sp;
var _cpu;
var el_string;
var rpm_spec_vers_cmp;
var epoch;
var allowmaj;
var exists_check;
var cves;
foreach var constraint ( constraints ) {
  # Check that the target release is equal to the affected release
  if (!empty_or_null(constraint['release'])){
    if (constraint['release'] != os_release) continue;
  }
  if (!empty_or_null(constraint['sp'])){
    if (constraint['sp'] != os_sp) continue;
  }
  foreach var pkg ( constraint['pkgs'] ) {
    reference = NULL;
    sp = NULL;
    _cpu = NULL;
    el_string = NULL;
    rpm_spec_vers_cmp = NULL;
    epoch = NULL;
    allowmaj = NULL;
    exists_check = NULL;
    cves = NULL;
    if (!empty_or_null(pkg['reference'])) reference = pkg['reference'];
    if (!empty_or_null(pkg['sp'])) sp = pkg['sp'];
    if (!empty_or_null(pkg['cpu'])) _cpu = pkg['cpu'];
    if (!empty_or_null(pkg['el_string'])) el_string = pkg['el_string'];
    if (!empty_or_null(pkg['rpm_spec_vers_cmp'])) rpm_spec_vers_cmp = pkg['rpm_spec_vers_cmp'];
    if (!empty_or_null(pkg['epoch'])) epoch = pkg['epoch'];
    if (!empty_or_null(pkg['allowmaj'])) allowmaj = pkg['allowmaj'];
    if (!empty_or_null(pkg['exists_check'])) exists_check = pkg['exists_check'];
    if (!empty_or_null(pkg['cves'])) cves = pkg['cves'];
    if (reference &&
        ## (no known rpm to check OR known rpm_exists)
        (!exists_check || rpm_exists(rpm:exists_check)) &&
        rpm_check(sp:sp, cpu:_cpu, reference:reference, epoch:epoch, el_string:el_string, rpm_spec_vers_cmp:rpm_spec_vers_cmp, allowmaj:allowmaj, cves:cves)) flag++;
  }
}


if (flag)
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : rpm_report_get()
  );
  exit(0);
}
else
{
  var tested = pkg_tests_get();
  if (tested) audit(AUDIT_PACKAGE_NOT_AFFECTED, tested);
  else audit(AUDIT_PACKAGE_NOT_INSTALLED, 'kernel');
}