The version of mtr as distributed in Debian GNU/Linux 2l1 (aka slink) did not drop root privileges correctly. While there are no known exploits it is conceivable that a weakness in gtk or ncurses could be used to exploit this.

This has been fixed in version 0.28-1, and we recommend that you upgrade your mtr package.

wget url
will fetch the file for you
dpkg -i file.deb
will install the referenced file.

Debian GNU/Linux 2.1 alias slink

Source archives:
http://security.debian.org/dists/stable/updates/source/mtr_0.28-1.diff.gz
MD5 checksum: a4fd6dbcc3b50914299b5de93d4b4ce8
http://security.debian.org/dists/stable/updates/source/mtr_0.28-1.dsc
MD5 checksum: 4570f1d02c68225e5819c0d41a9efb45
http://security.debian.org/dists/stable/updates/source/mtr_0.28.orig.tar.gz
MD5 checksum: 40074f51f01fbd295f330401175f9223

Alpha architecture:
http://security.debian.org/dists/stable/updates/binary-alpha/mtr_0.28-1_alpha.deb
MD5 checksum: 2aafabb8fe0e618030cdd5a5cab20769

Intel ia32 architecture:
http://security.debian.org/dists/stable/updates/binary-i386/mtr_0.28-1_i386.deb
MD5 checksum: b1f0fdfa4d213531bd613b69ebe62b14

Motorola 680x0 architecture:
http://security.debian.org/dists/stable/updates/binary-m68k/mtr_0.28-1_m68k.deb
MD5 checksum: 6c2089822ed8283885ccd6ab3564bf08

Sun Sparc architecture:
http://security.debian.org/dists/stable/updates/binary-sparc/mtr_0.28-1_sparc.deb
MD5 checksum: 024ee70deac4dcb0a78b2cb5eedd287e

These files will be moved into
ftp://ftp.debian.org/debian/dists/stable/*/binary-$arch/ soon.

For not yet released architectures please refer to the appropriate directory ftp://ftp.debian.org/debian/dists/sid/binary-$arch/ .