High severity · published Oct 6, 2026
CVE-2026-106117
ImageSharp: CCITT fax decompression (T4/Modified Huffman): unbounded WriteBits overflows strip buffer — heap OOB write in SixLabors.ImageSharp
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 32% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
IM
ImageSharp · SixLabors
>= 3.0.0, < 4.1.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-106117
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-106117
x_refsource_CONFIRM
https://github.com/SixLabors/ImageSharp/security/advisories/GHSA-jj3q-cwqj-842r
x_refsource_MISC
https://github.com/SixLabors/ImageSharp/pull/3176
x_refsource_MISC
https://github.com/SixLabors/ImageSharp/commit/e8892ecd8a95dee95c4480fda51cfe0b32f3b846
x_refsource_MISC
https://github.com/SixLabors/ImageSharp/releases/tag/v4.1.1
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