CVE-2017-6363: 
Linux Debian vulnerability analysis and mitigation

The vulnerability CVE-2017-6363 affects the GD Graphics Library (LibGD) through version 2.2.5. It involves a heap-based buffer over-read vulnerability in the tiffWriter function within gd_tiff.c. This vulnerability is disputed by the vendor, who argues that it should not have a CVE since the affected GD and GD2 formats are documented as obsolete and intended only for development and testing purposes (NVD).

The vulnerability manifests as an invalid read operation within the tiffWriter function of gd_tiff.c. When calling gdImageTiffPtr, multiple invalid read operations of size 4 bytes occur at different locations within an unallocated memory block. The issue was identified through fuzzing tests and confirmed using Valgrind memory analysis (Github Issue). The vulnerability has been assigned a CVSS v3.1 base score of 8.1 (HIGH) with vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H (NVD).

If exploited, this vulnerability could potentially lead to information exposure or system crashes. The impact is particularly relevant when processing GD and GD2 format files, though these formats are considered obsolete by the vendor (NVD).

The vulnerability affects Ubuntu 20.04 LTS, Ubuntu 18.04 LTS, Ubuntu 16.04 ESM, and Ubuntu 14.04 ESM systems. Updates have been released to address this issue in these affected versions (Ubuntu Notice).