GHSA-5VX3-WX4Q-6CJ8
Vulnerability from github – Published: 2026-01-21 01:06 – Updated: 2026-01-21 01:06
VLAI?
Summary
ImageMagick has a NULL pointer dereference in MSL parser via <comment> tag before image load
Details
Summary
NULL pointer dereference in MSL (Magick Scripting Language) parser when processing <comment> tag before any image is loaded.
Version
- ImageMagick 7.x (tested on current main branch)
- Commit: HEAD
Steps to Reproduce
Method 1: Using ImageMagick directly
magick MSL:poc.msl out.png
Method 2: Using OSS-Fuzz reproduce
python3 infra/helper.py build_fuzzers imagemagick
python3 infra/helper.py reproduce imagemagick msl_fuzzer poc.msl
Or run the fuzzer directly:
./msl_fuzzer poc.msl
Expected Behavior
ImageMagick should handle the malformed MSL gracefully and return an error message.
Actual Behavior
convert: MagickCore/property.c:297: MagickBooleanType DeleteImageProperty(Image *, const char *): Assertion `image != (Image *) NULL' failed.
Aborted
Root Cause Analysis
In 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:
if (LocaleCompare((const char *) tag,"comment") == 0 )
{
(void) DeleteImageProperty(msl_info->image[n],"comment"); // No NULL check
...
}
When <comment> appears before any <read> operation, msl_info->image[n] is NULL, causing the assertion failure in DeleteImageProperty() at property.c:297.
Impact
- DoS: Crash via assertion failure (debug builds) or NULL pointer dereference (release builds)
- Affected: Any application using ImageMagick to process user-supplied MSL files
Fuzzer
This issue was discovered using a custom MSL fuzzer:
#include <cstdint>
#include <Magick++/Blob.h>
#include <Magick++/Image.h>
#include "utils.cc"
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
{
if (IsInvalidSize(Size))
return(0);
try
{
const Magick::Blob blob(Data, Size);
Magick::Image image;
image.magick("MSL");
image.fileName("MSL:");
image.read(blob);
}
catch (Magick::Exception)
{
}
return(0);
}
This issue was found by Team FuzzingBrain @ Texas A&M University
Severity ?
6.5 (Medium)
{
"affected": [
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q8-x64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q8-arm64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q8-x86"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q8-OpenMP-x64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q8-OpenMP-arm64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-x64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-arm64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-x86"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-OpenMP-x64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-OpenMP-arm64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-OpenMP-x86"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-HDRI-x64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-HDRI-arm64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-HDRI-x86"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-HDRI-OpenMP-x64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-HDRI-OpenMP-arm64"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q8-AnyCPU"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-AnyCPU"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "NuGet",
"name": "Magick.NET-Q16-HDRI-AnyCPU"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "14.10.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-23952"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": true,
"github_reviewed_at": "2026-01-21T01:06:51Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "## Summary\n\nNULL pointer dereference in MSL (Magick Scripting Language) parser when processing `\u003ccomment\u003e` 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\u0027 failed.\nAborted\n```\n\n## Root Cause Analysis\n\nIn `coders/msl.c:7091`, `MSLEndElement()` calls `DeleteImageProperty()` on `msl_info-\u003eimage[n]` when handling the `\u003c/comment\u003e` 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-\u003eimage[n],\"comment\"); // No NULL check\n ...\n }\n```\n\nWhen `\u003ccomment\u003e` appears before any `\u003cread\u003e` operation, `msl_info-\u003eimage[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 \u003ccstdint\u003e\n#include \u003cMagick++/Blob.h\u003e\n#include \u003cMagick++/Image.h\u003e\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\u0026M University",
"id": "GHSA-5vx3-wx4q-6cj8",
"modified": "2026-01-21T01:06:51Z",
"published": "2026-01-21T01:06:51Z",
"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"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "ImageMagick has a NULL pointer dereference in MSL parser via \u003ccomment\u003e tag before image load"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…