* gnu/packages/patches/libtiff-CVE-2015-8665+CVE-2015-8683.patch, gnu/packages/patches/libtiff-oob-accesses-in-decode.patch, gnu/packages/patches/libtiff-oob-write-in-nextdecode.patch: New files. * gnu-system.am (dist_patch_DATA): Add them. * gnu/packages/image.scm (libtiff): Update to 4.0.6. [source]: Add patches.