EulerOS 2.0 SP15 : libpng (EulerOS-SA-2026-2489)

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

include('compat.inc');

if (description)
{
  script_id(323153);
  script_version("1.1");
  script_set_attribute(attribute:"plugin_modification_date", value:"2026/06/27");

  script_cve_id("CVE-2026-33416", "CVE-2026-33636", "CVE-2026-34757");
  script_xref(name:"IAVA", value:"2026-A-0272-S");
  script_xref(name:"IAVA", value:"2026-A-0322-S");

  script_name(english:"EulerOS 2.0 SP15 : libpng (EulerOS-SA-2026-2489)");

  script_set_attribute(attribute:"synopsis", value:
"The remote EulerOS host is missing multiple security updates.");
  script_set_attribute(attribute:"description", value:
"According to the versions of the libpng packages installed, the EulerOS installation on the remote host is affected by
the following vulnerabilities :

    LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable
    Network Graphics) raster image files. In versions 1.6.36 through 1.6.55, an out-of-bounds read and write
    exists in libpng's ARM/AArch64 Neon-optimized palette expansion path. When expanding 8-bit paletted rows
    to RGB or RGBA, the Neon loop processes a final partial chunk without verifying that enough input pixels
    remain. Because the implementation works backward from the end of the row, the final iteration
    dereferences pointers before the start of the row buffer (OOB read) and writes expanded pixel data to the
    same underflowed positions (OOB write). This is reachable via normal decoding of attacker-controlled PNG
    input if Neon is enabled. Version 1.6.56 fixes the issue.(CVE-2026-33636)

    LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable
    Network Graphics) raster image files. In versions 1.2.1 through 1.6.55, `png_set_tRNS` and `png_set_PLTE`
    each alias a heap-allocated buffer between `png_struct` and `png_info`, sharing a single allocation across
    two structs with independent lifetimes. The `trans_alpha` aliasing has been present since at least libpng
    1.0, and the `palette` aliasing since at least 1.2.1. Both affect all prior release lines `png_set_tRNS`
    sets `png_ptr-trans_alpha = info_ptr-trans_alpha` (256-byte buffer) and `png_set_PLTE` sets
    `info_ptr-palette = png_ptr-palette` (768-byte buffer). In both cases, calling `png_free_data` (with
    `PNG_FREE_TRNS` or `PNG_FREE_PLTE`) frees the buffer through `info_ptr` while the corresponding `png_ptr`
    pointer remains dangling. Subsequent row-transform functions dereference and, in some code paths, write to
    the freed memory. A second call to `png_set_tRNS` or `png_set_PLTE` has the same effect, because both
    functions call `png_free_data` internally before reallocating the `info_ptr` buffer. Version 1.6.56 fixes
    the issue.(CVE-2026-33416)

    LIBPNG is a reference library for use in applications that read, create, and manipulate PNG (Portable
    Network Graphics) raster image files. From 1.0.9 to before 1.6.57, passing a pointer obtained from
    png_get_PLTE, png_get_tRNS, or png_get_hIST back into the corresponding setter on the same
    png_struct/png_info pair causes the setter to read from freed memory and copy its contents into the
    replacement buffer. The setter frees the internal buffer before copying from the caller-supplied pointer,
    which now dangles. The freed region may contain stale data (producing silently corrupted chunk metadata)
    or data from subsequent heap allocations (leaking unrelated heap contents into the chunk struct). This
    vulnerability is fixed in 1.6.57.(CVE-2026-34757)

Tenable has extracted the preceding description block directly from the EulerOS libpng security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version
number.");
  # https://developer.huaweicloud.com/ict/en/site-euleros/euleros/security-advisories/EulerOS-SA-2026-2489
  script_set_attribute(attribute:"see_also", value:"http://www.nessus.org/u?8b036698");
  script_set_attribute(attribute:"solution", value:
"Update the affected libpng packages.");
  script_set_cvss_base_vector("CVSS2#AV:L/AC:L/Au:S/C:P/I:P/A:N");
  script_set_cvss_temporal_vector("CVSS2#E:POC/RL:OF/RC:C");
  script_set_cvss3_base_vector("CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N");
  script_set_cvss3_temporal_vector("CVSS:3.0/E:P/RL:O/RC:C");
  script_set_attribute(attribute:"cvss_score_source", value:"CVE-2026-34757");

  script_set_attribute(attribute:"exploitability_ease", value:"Exploits are available");
  script_set_attribute(attribute:"exploit_available", value:"true");

  script_set_attribute(attribute:"vuln_publication_date", value:"2026/03/10");
  script_set_attribute(attribute:"patch_publication_date", value:"2026/06/26");
  script_set_attribute(attribute:"plugin_publication_date", value:"2026/06/27");

  script_set_attribute(attribute:"plugin_type", value:"local");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libpng");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libpng-devel");
  script_set_attribute(attribute:"cpe", value:"p-cpe:/a:huawei:euleros:libpng-help");
  script_set_attribute(attribute:"cpe", value:"cpe:/o:huawei:euleros:2.0");
  script_set_attribute(attribute:"generated_plugin", value:"current");
  script_set_attribute(attribute:"stig_severity", value:"I");
  script_end_attributes();

  script_category(ACT_GATHER_INFO);
  script_family(english:"Huawei 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_info.nasl");
  script_require_keys("Host/local_checks_enabled", "Host/cpu", "Host/EulerOS/release", "Host/EulerOS/rpm-list", "Host/EulerOS/sp");
  script_exclude_keys("Host/EulerOS/uvp_version");

  exit(0);
}

include("rpm.inc");

if (!get_kb_item("Host/local_checks_enabled")) audit(AUDIT_LOCAL_CHECKS_NOT_ENABLED);

var _release = get_kb_item("Host/EulerOS/release");
if (isnull(_release) || _release !~ "^EulerOS") audit(AUDIT_OS_NOT, "EulerOS");
var uvp = get_kb_item("Host/EulerOS/uvp_version");
if (_release !~ "^EulerOS release 2\.0(\D|$)") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP15");

var sp = get_kb_item("Host/EulerOS/sp");
if (isnull(sp) || sp !~ "^(15)$") audit(AUDIT_OS_NOT, "EulerOS 2.0 SP15");

if (!empty_or_null(uvp)) audit(AUDIT_OS_NOT, "EulerOS 2.0 SP15", "EulerOS UVP " + uvp);

if (!get_kb_item("Host/EulerOS/rpm-list")) audit(AUDIT_PACKAGE_LIST_MISSING);

var cpu = get_kb_item("Host/cpu");
if (isnull(cpu)) audit(AUDIT_UNKNOWN_ARCH);
if ("x86_64" >!< cpu && cpu !~ "^i[3-6]86$" && "aarch64" >!< cpu && "x86" >!< cpu) audit(AUDIT_LOCAL_CHECKS_NOT_IMPLEMENTED, "EulerOS", cpu);
if ("aarch64" >!< cpu) audit(AUDIT_ARCH_NOT, "aarch64", cpu);

var flag = 0;

var pkgs = [
  "libpng-1.6.40-1.h21510.7.eulerosv2r15",
  "libpng-devel-1.6.40-1.h21510.7.eulerosv2r15",
  "libpng-help-1.6.40-1.h21510.7.eulerosv2r15"
];

foreach (var pkg in pkgs)
  if (rpm_check(release:"EulerOS-2.0", sp:"15", reference:pkg)) flag++;

if (flag)
{
  security_report_v4(
    port       : 0,
    severity   : SECURITY_NOTE,
    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, "libpng");
}