CVE-2026-106110

ImageSharp: TIFF CCITT T4 encoder can write past its compressed output buffer

Published Oct 6, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed

Description

ImageSharp is a 2D graphics library. From 2.0.0 until 4.1.2, the TIFF CCITT Group 3 encoder allocates an undersized compressed-data buffer for narrow 1-bit images. TiffCcittCompressor.Initialize does not reserve enough space for the row data and T4 end-of-line codes, and T4BitCompressor.CompressStrip reaches unchecked writes when TiffCompression.CcittGroup3Fax is selected directly or inherited from decoded TIFF metadata. An attacker-controlled encode or decode-and-re-encode flow can write beyond the logical output span, corrupt process memory, and terminate the process. This issue is fixed in version 4.1.2.

Analysis

Technical impact

The flaw in ImageSharp’s TIFF CCITT Group 3 encoder originates from an undersized buffer for narrow 1‑bit images. When encoding these images, the encoder writes beyond the allocated memory, corrupting the process’s memory space and causing a crash. The memory overwrite could, in theory, be manipulated to execute arbitrary code, but the confirmed impact is process termination and potential denial of service.

Affected Systems

ImageSharp releases from 2.0.0 through 4.1.1 are affected. The vulnerability is fixed in version 4.1.2, which should be used for all .NET applications that render or regenerate TIFF images.

Risk and Exploitability

The CVSS score of 7.5 rates this flaw as High severity. While the EPSS score is not available and the vulnerability is not listed in the CISA KEV catalog, attacker‑controlled encode or decode‑and‑re‑encode flows can trigger the overflow. The risk is elevated for services that expose the encoder to untrusted data or run with elevated privileges; it could lead to a denial of service or, in worst cases, arbitrary code execution.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

SixLabors

ImageSharp

affected

Version	Status	Constraints
`>= 2.0.0, < 4.1.2`	affected	—

Configuration 1 [-]

OR	cpe:2.3:a:sixlabors:imagesharp::::::::
	cpe:2.3:a:sixlabors:imagesharp::::::::

No data.

Vendor Product Versions

Sixlabors

Imagesharp

Version	Status	Scheme	Platform
`[2.0.0,4.1.2)`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Upgrade the ImageSharp library to version 4.1.2 or later, which contains the buffer‑allocation fix.
If an immediate upgrade is not possible, remove or disable usage of the CCITT Group 3 encoder for thin 1‑bit TIFF images in your application until the library is updated.
Restrict the acceptance of untrusted TIFF files and validate compression parameters in your own code, ensuring that only supported compression schemes are processed.

Generated by OpenCVE AI on October 6, 2026 at 19:10 UTC.

Tracking

Advisories

Source	ID	Title
Github GHSA	GHSA-j9gm-c75j-xc9q	ImageSharp: TIFF CCITT T4 encoder can write past its compressed output buffer

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.385% probability within 30 days)

Exploitation poc

Automatable yes

Technical Impact partial

References

Link	Providers
https://github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc81e706914ac16a95
https://github.com/SixLabors/ImageSharp/pull/3187
https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2
https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-j9gm-c75j-xc9q

History

Oct 24, 2026 2:00 AM Affected versions updated View changes

Type	Values Removed	Values Added
CPEs		cpe:2.3:a:sixlabors:imagesharp::::::::

Oct 9, 2026 2:30 AM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Oct 7, 2026 6:15 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Sixlabors Sixlabors imagesharp
Vendors & Products		Sixlabors Sixlabors imagesharp

Oct 6, 2026 5:45 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		ImageSharp is a 2D graphics library. From 2.0.0 until 4.1.2, the TIFF CCITT Group 3 encoder allocates an undersized compressed-data buffer for narrow 1-bit images. TiffCcittCompressor.Initialize does not reserve enough space for the row data and T4 end-of-line codes, and T4BitCompressor.CompressStrip reaches unchecked writes when TiffCompression.CcittGroup3Fax is selected directly or inherited from decoded TIFF metadata. An attacker-controlled encode or decode-and-re-encode flow can write beyond the logical output span, corrupt process memory, and terminate the process. This issue is fixed in version 4.1.2.
Title		ImageSharp: TIFF CCITT T4 encoder can write past its compressed output buffer
Weaknesses		CWE-787
References		https://github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc81e706914ac16a95 https://github.com/SixLabors/ImageSharp/pull/3187 https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.2 https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-j9gm-c75j-xc9q
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}`