An integer underflow in the exif_entry_get_value function can cause a heap overflow and potentially arbitrary code execution while formatting an EXIF tag, if the function is called with a buffer size parameter equal to zero or one.
This now public via exif 0.6.21: http://libexif.cvs.sourceforge.net/viewvc/libexif/libexif/ChangeLog?revision=1.370 http://libexif.cvs.sourceforge.net/viewvc/libexif/libexif/libexif/exif-entry.c?r1=1.148&r2=1.149&view=patch
Created libexif tracking bugs for this issue Affects: fedora-all [bug 839917]
Upstream advisory: http://sourceforge.net/mailarchive/message.php?msg_id=29534027
Acknowledgements: Red Hat would like to thank Dan Fandrich for reporting this issue.
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 5 Via RHSA-2012:1255 https://rhn.redhat.com/errata/RHSA-2012-1255.html
libexif-0.6.21-2.fc16 has been pushed to the Fedora 16 stable repository. If problems still persist, please make note of it in this bug report.
libexif-0.6.21-2.fc17 has been pushed to the Fedora 17 stable repository. If problems still persist, please make note of it in this bug report.