Linux Distros Unpatched Vulnerability : CVE-2026-45839

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

include('compat.inc');

if (description)
{
  script_id(317077);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/05/27");

  script_cve_id("CVE-2026-45839");

  script_name(english:"Linux Distros Unpatched Vulnerability : CVE-2026-45839");

  script_set_attribute(attribute:"synopsis", value:
"The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be
patched.");
  script_set_attribute(attribute:"description", value:
"The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied
patch available.

  - bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec() CO-RE accessor strings are colon-
    separated indices that describe a path from a root BTF type to a target field, e.g. 0:1:2 walks through
    nested struct members. bpf_core_parse_spec() parses each component with sscanf(%d), so negative values
    like -1 are silently accepted. The subsequent bounds checks (access_idx >= btf_vlen(t)) only guard the
    upper bound and always pass for negative values because C integer promotion converts the __u16 btf_vlen
    result to int, making the comparison (int)(-1) >= (int)(N) false for any positive N. When -1 reaches
    btf_member_bit_offset() it gets cast to u32 0xffffffff, producing an out-of-bounds read far past the
    members array. A crafted BPF program with a negative CO-RE accessor on any struct that exists in vmlinux
    BTF (e.g. task_struct) crashes the kernel deterministically during BPF_PROG_LOAD on any system with
    CONFIG_DEBUG_INFO_BTF=y (default on major distributions). The bug is reachable with CAP_BPF: BUG: unable
    to handle page fault for address: ffffed11818b6626 #PF: supervisor read access in kernel mode #PF:
    error_code(0x0000) - not-present page Oops: Oops: 0000 [#1] SMP KASAN NOPTI CPU: 0 UID: 0 PID: 85 Comm:
    poc Not tainted 7.0.0-rc6 #18 PREEMPT(full) RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354)
    RAX: 00000000ffffffff Call Trace: <TASK> bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321)
    bpf_core_apply (kernel/bpf/btf.c:9507) check_core_relo (kernel/bpf/verifier.c:19475) bpf_check
    (kernel/bpf/verifier.c:26031) bpf_prog_load (kernel/bpf/syscall.c:3089) __sys_bpf
    (kernel/bpf/syscall.c:6228) </TASK> CO-RE accessor indices are inherently non-negative (struct member
    index, array element index, or enumerator index), so reject them immediately after parsing.
    (CVE-2026-45839)

Note that Nessus relies on the presence of the package as reported by the vendor.");
  script_set_attribute(attribute:"see_also", value:"https://security-tracker.debian.org/tracker/CVE-2026-45839");
  script_set_attribute(attribute:"solution", value:
"There is no known solution at this time.");
  script_set_attribute(attribute:"agent", value:"unix");
  script_set_cvss_base_vector("CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P");
  script_set_cvss_temporal_vector("CVSS2#E:U/RL:U/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:U/RL:U/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-45839");

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

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/05/27");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/05/27");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:11.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:12.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:13.0");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:debian:debian_linux:14.0");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:debian:debian_linux:linux");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Misc.");

  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", "set_linux_os_id.nasl");
  script_require_keys("Host/cpu", "Host/local_checks_enabled", "global_settings/vendor_unpatched", "Host/OS/identifier");
  script_require_ports("Host/OS/Debian Linux-11", "Host/OS/Debian Linux-12", "Host/OS/Debian Linux-13", "Host/OS/Debian Linux-14");

  exit(0);
}

if (!get_kb_item("global_settings/vendor_unpatched")) exit(0, "Unpatched Vulnerabilities Detection not active.");
if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);
if (empty_or_null(get_one_kb_item("Host/Debian/dpkg-l"))) audit(AUDIT_PACKAGE_LIST_MISSING);

include('linux_unpatched.inc');

var distro_constraints_array = {
  "Debian Linux-12": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "12",
        "pkgs": [
          {"reference": "btrfs-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "cdrom-core-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "ext4-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "fat-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "isofs-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "jfs-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "kernel-image-6.1.0-47-alpha-generic-di"},
          {"reference": "linux-doc"},
          {"reference": "linux-doc-6.1"},
          {"reference": "linux-headers-6.1.0"},
          {"reference": "linux-source"},
          {"reference": "linux-source-6.1"},
          {"reference": "linux-support-6.1.0"},
          {"reference": "loop-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "nic-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "nic-shared-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "nic-wireless-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "pata-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "ppp-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "scsi-core-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "scsi-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "scsi-nic-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "serial-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "usb-serial-modules-6.1.0-47-alpha-generic-di"},
          {"reference": "xfs-modules-6.1.0-47-alpha-generic-di"}
        ]
      }
    ]
  },
  "Debian Linux-11": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "11",
        "pkgs": [
          {"reference": "bpftool"},
          {"reference": "btrfs-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "cdrom-core-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "hyperv-daemons"},
          {"reference": "kernel-image-5.10.0-32-alpha-generic-di"},
          {"reference": "libcpupower-dev"},
          {"reference": "libcpupower1"},
          {"reference": "linux-bootwrapper-5.10.0"},
          {"reference": "linux-config-5.10"},
          {"reference": "linux-cpupower"},
          {"reference": "linux-doc"},
          {"reference": "linux-doc-5.10"},
          {"reference": "linux-headers-5.10.0"},
          {"reference": "linux-kbuild-5.10"},
          {"reference": "linux-libc-dev"},
          {"reference": "linux-perf"},
          {"reference": "linux-perf-5.10"},
          {"reference": "linux-source"},
          {"reference": "linux-source-5.10"},
          {"reference": "linux-support-5.10.0"},
          {"reference": "loop-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "nic-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "nic-shared-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "nic-wireless-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "pata-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "ppp-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "scsi-core-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "scsi-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "scsi-nic-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "serial-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "usb-serial-modules-5.10.0-32-alpha-generic-di"},
          {"reference": "usbip"}
        ]
      }
    ]
  },
  "Debian Linux-14": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "14",
        "pkgs": [
          {"reference": "bpftool"},
          {"reference": "hyperv-daemons"},
          {"reference": "intel-sdsi"},
          {"reference": "libcpupower-dev"},
          {"reference": "libcpupower1"},
          {"reference": "linux-base-7.0.9+deb14-alpha-generic"},
          {"reference": "linux-base-7.0.9+deb14-alpha-smp"},
          {"reference": "linux-base-7.0.9+deb14-amd64"},
          {"reference": "linux-base-7.0.9+deb14-arm64"},
          {"reference": "linux-base-7.0.9+deb14-arm64-16k"},
          {"reference": "linux-base-7.0.9+deb14-armmp"},
          {"reference": "linux-base-7.0.9+deb14-armmp-lpae"},
          {"reference": "linux-base-7.0.9+deb14-cloud-amd64"},
          {"reference": "linux-base-7.0.9+deb14-cloud-arm64"},
          {"reference": "linux-base-7.0.9+deb14-loong64"},
          {"reference": "linux-base-7.0.9+deb14-m68k"},
          {"reference": "linux-base-7.0.9+deb14-parisc"},
          {"reference": "linux-base-7.0.9+deb14-parisc64"},
          {"reference": "linux-base-7.0.9+deb14-powerpc"},
          {"reference": "linux-base-7.0.9+deb14-powerpc-smp"},
          {"reference": "linux-base-7.0.9+deb14-powerpc64"},
          {"reference": "linux-base-7.0.9+deb14-powerpc64-64k"},
          {"reference": "linux-base-7.0.9+deb14-powerpc64le"},
          {"reference": "linux-base-7.0.9+deb14-powerpc64le-64k"},
          {"reference": "linux-base-7.0.9+deb14-riscv64"},
          {"reference": "linux-base-7.0.9+deb14-rt-amd64"},
          {"reference": "linux-base-7.0.9+deb14-rt-arm64"},
          {"reference": "linux-base-7.0.9+deb14-s390x"},
          {"reference": "linux-base-7.0.9+deb14-sh7751r"},
          {"reference": "linux-base-7.0.9+deb14-sparc64"},
          {"reference": "linux-base-7.0.9+deb14-sparc64-smp"},
          {"reference": "linux-base-7.0.9+deb14-test"}
        ]
      }
    ]
  },
  "Debian Linux-13": {
    "package_manager": "dpkg-l",
    "constraints": [
      {
        "release": "13",
        "pkgs": [
          {"reference": "bpftool"},
          {"reference": "hyperv-daemons"},
          {"reference": "intel-sdsi"},
          {"reference": "libcpupower-dev"},
          {"reference": "libcpupower1"},
          {"reference": "linux-bpf-dev"},
          {"reference": "linux-config-6.12"},
          {"reference": "linux-cpupower"},
          {"reference": "linux-doc"},
          {"reference": "linux-doc-6.12"},
          {"reference": "linux-headers-4kc-malta"},
          {"reference": "linux-headers-5kc-malta"},
          {"reference": "linux-headers-6.12.86+deb13-4kc-malta"},
          {"reference": "linux-headers-6.12.86+deb13-5kc-malta"},
          {"reference": "linux-headers-6.12.86+deb13-alpha-generic"},
          {"reference": "linux-headers-6.12.86+deb13-alpha-smp"},
          {"reference": "linux-headers-6.12.86+deb13-amd64"},
          {"reference": "linux-headers-6.12.86+deb13-arm64"},
          {"reference": "linux-headers-6.12.86+deb13-arm64-16k"},
          {"reference": "linux-headers-6.12.86+deb13-armmp"},
          {"reference": "linux-headers-6.12.86+deb13-armmp-lpae"},
          {"reference": "linux-headers-6.12.86+deb13-cloud-amd64"},
          {"reference": "linux-headers-6.12.86+deb13-cloud-arm64"},
          {"reference": "linux-headers-6.12.86+deb13-common"},
          {"reference": "linux-headers-6.12.86+deb13-common-rt"},
          {"reference": "linux-headers-6.12.86+deb13-loong64"},
          {"reference": "linux-headers-6.12.86+deb13-loongson-3"},
          {"reference": "linux-headers-6.12.86+deb13-m68k"},
          {"reference": "linux-headers-6.12.86+deb13-mips32r2eb"},
          {"reference": "linux-headers-6.12.86+deb13-mips32r2el"},
          {"reference": "linux-headers-6.12.86+deb13-mips64r2eb"},
          {"reference": "linux-headers-6.12.86+deb13-mips64r2el"}
        ]
      }
    ]
  }
};

var distro_constraints_values = linux_unpatched::get_distro_constraints(distro_constraints_arr:distro_constraints_array);
if (empty_or_null(distro_constraints_values)) audit(AUDIT_HOST_NOT, 'affected');
var report = linux_unpatched::check_unpatched_constraints(distro_constraints_values:distro_constraints_values);

if (!empty_or_null(report))
{
  security_report_v4(
      port       : 0,
      severity   : SECURITY_WARNING,
      extra      : report
  );
  exit(0);
}
else
{
  audit(AUDIT_HOST_NOT, 'affected');
}