ImageSharp is a 2D graphics library. From 2.1.0 until 4.1.2, the TIFF CCITT Group 4 encoder allocates Width times rowsPerStrip bytes even though T6BitCompressor.CompressStrip can emit encoded row data and two 12-bit end-of-facsimile-block codes beyond that capacity. TiffCcittCompressor.WriteCode performs unchecked writes, and a decode-and-re-encode flow can inherit TiffCompression.CcittGroup4Fax and one-bit metadata from attacker-supplied input. The resulting out-of-bounds writes can corrupt memory and terminate the process.
This issue is fixed in version 4.1.2.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service
CVSS Vector v3.1
Weakness Type (CWE)
References 4
https://github.com/SixLabors/ImageSharp/commit/a9498c6db3642ef92c712ebc81e70691…
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-jjfr-hcj7-qf5w
security-advisories@github.com