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TI-2026-68635 Aliases CVE-2026-106116GHSA-wmxv-xphr-5c9g

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

Priority MEDIUM 63CWE-835Published · 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 · Low
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-835.

Summary

ExifReader.ReadValues64 in ImageSharp trusts the 64-bit BigTIFF IFD entry count and iterates once per declared entry, in versions from 2.0.0 before 4.1.2. When fewer than 20 bytes remain, ExifReader.ReadValue64 returns without advancing the stream or ending the outer loop, so a small malformed BigTIFF can keep one decoder thread running for an attacker-chosen time. The report does not claim worker-pool exhaustion. The weakness is CWE-835 (Loop with Unreachable Exit Condition).

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

Description from the CNA

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00328 26th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed ImageSharp (SixLabors): 4.1.2SixLabors.ImageSharp (NuGet): 3.2.0, 4.1.2

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
SixLaborsImageSharp2.0.0 to before 4.1.24.1.2Patch availableCNA
—SixLabors.ImageSharp (NuGet)2.0.0 to before 3.2.03.2.0Patch availableGHSA-wmxv-xphr-5c9g
—SixLabors.ImageSharp (NuGet)4.0.0 to before 4.1.24.1.2Patch availableGHSA-wmxv-xphr-5c9g
  • ImageSharp VendorSixLabors Affected 2.0.0 to before 4.1.2 Fixed in 4.1.2 Patch available CNA
  • SixLabors.ImageSharp (NuGet) Vendor— Affected 2.0.0 to before 3.2.0 Fixed in 3.2.0 Patch available GHSA-wmxv-xphr-5c9g
  • SixLabors.ImageSharp (NuGet) Vendor— Affected 4.0.0 to before 4.1.2 Fixed in 4.1.2 Patch available GHSA-wmxv-xphr-5c9g

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:sixlabors:imagesharp:*:*:*:*:*:*:*:*2.0.0 to before 3.2.0; 4.0.0 to before 4.1.2VulnerableSixLabors
  • cpe:2.3:a:sixlabors:imagesharp:*:*:*:*:*:*:*:* Versions 2.0.0 to before 3.2.0; 4.0.0 to before 4.1.2 Vulnerable ·SixLabors

Remediation

Upgrade ImageSharp to version 4.1.2 or later. For the NuGet package SixLabors.ImageSharp, use 3.2.0 on the 2.0.0 to 3.2.0 line and 4.1.2 on the 4.0.0 to 4.1.2 line.

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

  • Fix · CNA ImageSharp (SixLabors) Fixed in 4.1.2
  • Fix · GHSA-wmxv-xphr-5c9g SixLabors.ImageSharp (NuGet) Fixed in 3.2.0 Advisory →
  • Fix · GHSA-wmxv-xphr-5c9g SixLabors.ImageSharp (NuGet) Fixed in 4.1.2 Advisory →

Timeline

  1. 2026-10-06 Threatist record created from CVE-2026-106116
  2. 2026-10-07 Alias added: GHSA-wmxv-xphr-5c9g
  3. 2026-10-07 Fix available: NuGet/[email protected] · GHSA-wmxv-xphr-5c9g
  4. 2026-10-07 CVSS score added · GHSA-wmxv-xphr-5c9g
  5. 2026-10-07 Weakness changed · GHSA-wmxv-xphr-5c9g
  6. 2026-10-07 6 new references · GHSA-wmxv-xphr-5c9g

References

Exploit 1

Patch 2

Advisory 1

Other 5

  • TI-2026-68636 Out-of-bounds write in ImageSharp CCITT fax decompression CVSS 3.1HIGH 7.5
  • 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-2026-68633 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