D. J. Bernstein reports that Bartlomiej Sieka has discovered several security vulnerabilities in lppasswd, which is part of CUPS. In the following excerpt from Bernstein's email, CVE names have been added for each issue:
First, lppasswd blithely ignores write errors in fputs(line,outfile) at lines 311 and 315 of lppasswd.c, and in fprintf(...) at line 346. An attacker who fills up the disk at the right moment can arrange for /usr/local/etc/cups/passwd to be truncated. (CAN-2004-1268) Second, if lppasswd bumps into a file-size resource limit while writing passwd.new, it leaves passwd.new in place, disabling all subsequent invocations of lppasswd. Any local user can thus disable lppasswd... (CAN-2004-1269) Third, line 306 of lppasswd.c prints an error message to stderr but does not exit. This is not a problem on systems that ensure that file descriptors 0, 1, and 2 are open for setuid programs, but it is a problem on other systems; lppasswd does not check that passwd.new is different from stderr, so it ends up writing a user-controlled error message to passwd if the user closes file descriptor 2. (CAN-2004-1270)
Note: The third issue, CVE-2004-1270, does not affect FreeBSD 4.6-RELEASE or later systems, as these systems ensure that the file descriptors 0, 1, and 2 are always open for set-user-ID and set-group-ID programs.