Steve Kemp discovered a buffer overflow in zblast-svgalib, when saving the high score file. This vulnerability could be exploited by a local user to gain gid 'games', if they can achieve a high score.
For the current stable distribution (woody) this problem has been fixed in version 1.2pre-5woody2.
For the unstable distribution (sid) this problem is fixed in version 1.2.1-7.
We recommend that you update your zblast package.
MD5 checksums of the listed files are available in the original advisory.