Read the docs
TI-2026-68636 Aliases CVE-2026-106117GHSA-jj3q-cwqj-842r

Out-of-bounds write in ImageSharp CCITT fax decompression

Priority HIGH 72CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-787 and the CVSS impact.

Summary

SixLabors ImageSharp from 3.0.0 before 4.1.1 is affected. Decoding a strip TIFF that uses CCITT Group 3 or Modified Huffman compression passes attacker-expanded runs to the bit writer without first checking the row width, which can overflow the strip buffer (CWE-787). An unauthenticated remote attacker can corrupt heap memory and terminate the process with a crafted TIFF file. A public exploit is linked in the references.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

ImageSharp is a 2D graphics library. From 3.0.0 until 4.1.1, decoding a strip TIFF using CCITT Group 3 or Modified Huffman compression can pass attacker-expanded runs to BitWriterUtils.WriteBits without first checking the current row width. T4TiffCompression.WritePixelRun can accumulate oversized makeup-code runs, and ModifiedHuffmanTiffCompression.Decompress validates the width only after writing. The unchecked writes can overflow the strip buffer, corrupt heap memory, and terminate the process. This strip-path vulnerability is distinct from the tiled decompressor-width mismatch. This issue is fixed in version 4.1.1.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00385 32nd percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed ImageSharp (SixLabors): 4.1.1ImageSharp (NuGet): 3.2.0, 4.1.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
SixLaborsImageSharp3.0.0 to before 4.1.14.1.1Patch availableCNA
—ImageSharp (NuGet)3.0.0 to before 3.2.03.2.0Patch availableGHSA-jj3q-cwqj-842r
—ImageSharp (NuGet)4.0.0 to before 4.1.14.1.1Patch availableGHSA-jj3q-cwqj-842r
  • ImageSharp VendorSixLabors Affected 3.0.0 to before 4.1.1 Fixed in 4.1.1 Patch available CNA
  • ImageSharp (NuGet) Vendor— Affected 3.0.0 to before 3.2.0 Fixed in 3.2.0 Patch available GHSA-jj3q-cwqj-842r
  • ImageSharp (NuGet) Vendor— Affected 4.0.0 to before 4.1.1 Fixed in 4.1.1 Patch available GHSA-jj3q-cwqj-842r

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:sixlabors:imagesharp:*:*:*:*:*:*:*:*3.0.0 to before 3.2.0; 4.0.0 to before 4.1.1VulnerableSixLabors
  • cpe:2.3:a:sixlabors:imagesharp:*:*:*:*:*:*:*:* Versions 3.0.0 to before 3.2.0; 4.0.0 to before 4.1.1 Vulnerable ·SixLabors

Remediation

Upgrade the NuGet package ImageSharp to 3.2.0 on the 3.x line or to 4.1.1 on the 4.x line.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA ImageSharp (SixLabors) Fixed in 4.1.1
  • Fix · GHSA-jj3q-cwqj-842r ImageSharp (NuGet) Fixed in 3.2.0 Advisory →
  • Fix · GHSA-jj3q-cwqj-842r ImageSharp (NuGet) Fixed in 4.1.1 Advisory →

Timeline

  1. 2026-10-06 Threatist record created from CVE-2026-106117
  2. 2026-10-07 Alias added: GHSA-jj3q-cwqj-842r
  3. 2026-10-07 Fix available: NuGet/[email protected] · GHSA-jj3q-cwqj-842r
  4. 2026-10-07 CVSS score added · GHSA-jj3q-cwqj-842r
  5. 2026-10-07 Weakness changed · GHSA-jj3q-cwqj-842r
  6. 2026-10-07 6 new references · GHSA-jj3q-cwqj-842r
  7. 2026-10-12 Fix available: NuGet/[email protected] · GHSA-jj3q-cwqj-842r
  8. 2026-10-12 1 new reference · GHSA-jj3q-cwqj-842r

References

Exploit 1

Patch 2

Advisory 1

Other 3

  • TI-2026-68634 Out-of-bounds write in ImageSharp TIFF CCITT Group 4 encoder CVSS 3.1HIGH 7.5
  • TI-2026-68629 Out-of-bounds write in ImageSharp TIFF CCITT encoder CVSS 3.1HIGH 7.5
  • TI-2025-20408 Out-of-bounds Write in SixLabors ImageSharp CVSS 3.1HIGH 7.5
  • TI-2026-68635 ImageSharp BigTIFF IFD count can keep a decoder thread in a non-progressing loop CVSS 3.1MEDIUM 5.3
  • TI-2026-68633 Excessive memory allocation in ImageSharp ICC CLUT parsing CVSS 3.1MEDIUM 5.3
  • TI-2026-68630 Stale buffer data disclosure in ImageSharp EXR ZIP decoding CVSS 3.1MEDIUM 5.9
See all 13 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences