An issue was discovered in gThumb through 3.6.2. There is a double-free vulnerability in the addthemesfromdir method in dlg-contact-sheet.c because of two successive calls of gfree, each of which frees the same buffer.
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2018-18718.json"