Andrea Barisani discovered that xzgv, a picture viewer for X with a thumbnail-based selector, attempts to decode JPEG images within the CMYK/YCCK colour space incorrectly, which could lead to the execution of arbitrary code.
For the old stable distribution (woody) this problem has been fixed in version 0.7-6woody3.
For the stable distribution (sarge) this problem has been fixed in version 0.8-3sarge1.
For the unstable distribution (sid) this problem will be fixed soon.
We recommend that you upgrade your xzgv package.