CVE-2026-23952: Magick.NET Q8 x64 ImageMagick Has A NULL Pointer Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5vx3-wx4q-6cj8",
  "modified" : "2026-01-21T01:06:51Z",
  "published" : "2026-01-21T01:06:51Z",
  "aliases" : [ "CVE-2026-23952" ],
  "summary" : "ImageMagick has a NULL pointer dereference in MSL parser via <comment> tag before image load",
  "details" : "## Summary\n\nNULL pointer dereference in MSL (Magick Scripting Language) parser when processing `<comment>` tag before any image is loaded.\n\n## Version\n\n- ImageMagick 7.x (tested on current main branch)\n- Commit: HEAD\n\n## Steps to Reproduce\n\n### Method 1: Using ImageMagick directly\n\n```bash\nmagick MSL:poc.msl out.png\n```\n\n### Method 2: Using OSS-Fuzz reproduce\n\n```bash\npython3 infra/helper.py build_fuzzers imagemagick\npython3 infra/helper.py reproduce imagemagick msl_fuzzer poc.msl\n```\n\nOr run the fuzzer directly:\n```bash\n./msl_fuzzer poc.msl\n```\n\n## Expected Behavior\n\nImageMagick should handle the malformed MSL gracefully and return an error message.\n\n## Actual Behavior\n\n```\nconvert: MagickCore/property.c:297: MagickBooleanType DeleteImageProperty(Image *, const char *): Assertion `image != (Image *) NULL' failed.\nAborted\n```\n\n## Root Cause Analysis\n\nIn `coders/msl.c:7091`, `MSLEndElement()` calls `DeleteImageProperty()` on `msl_info->image[n]` when handling the `</comment>` end tag without checking if the image is NULL:\n\n```c\nif (LocaleCompare((const char *) tag,\"comment\") == 0 )\n  {\n    (void) DeleteImageProperty(msl_info->image[n],\"comment\");  // No NULL check\n    ...\n  }\n```\n\nWhen `<comment>` appears before any `<read>` operation, `msl_info->image[n]` is NULL, causing the assertion failure in `DeleteImageProperty()` at `property.c:297`.\n\n## Impact\n\n- **DoS**: Crash via assertion failure (debug builds) or NULL pointer dereference (release builds)\n- **Affected**: Any application using ImageMagick to process user-supplied MSL files\n\n## Fuzzer\n\nThis issue was discovered using a custom MSL fuzzer:\n\n```cpp\n#include <cstdint>\n#include <Magick++/Blob.h>\n#include <Magick++/Image.h>\n#include \"utils.cc\"\n\nextern \"C\" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)\n{\n  if (IsInvalidSize(Size))\n    return(0);\n  try\n  {\n    const Magick::Blob blob(Data, Size);\n    Magick::Image image;\n    image.magick(\"MSL\");\n    image.fileName(\"MSL:\");\n    image.read(blob);\n  }\n  catch (Magick::Exception)\n  {\n  }\n  return(0);\n}\n```\n\nThis issue was found by Team FuzzingBrain @ Texas A&M University",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
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      "name" : "Magick.NET-Q8-x64"
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        "fixed" : "14.10.2"
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  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ImageMagick/ImageMagick/security/advisories/GHSA-5vx3-wx4q-6cj8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ImageMagick/ImageMagick"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/dlemstra/Magick.NET/releases/tag/14.10.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-476" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-21T01:06:51Z",
    "nvd_published_at" : null
  }
}