Exiv2 is a C++ library and a command-line utility to read, write, delete and modify Exif, IPTC, XMP and ICC image metadata. An out-of-bounds write was found in Exiv2 version v0.28.0. The vulnerable function, `BmffImage::brotliUncompress`, is new in v0.28.0, so earlier versions of Exiv2 are _not_ affected. The out-of-bounds write is triggered when Exiv2 is used to read the metadata of a crafted image file. An attacker could potentially exploit the vulnerability to gain code execution, if they can trick the victim into running Exiv2 on a crafted image file. This bug is fixed in version v0.28.1. Users are advised to upgrade. There are no known workarounds for this vulnerability.