How to Report A Bug

If you find a bug in ClamAV, please check it against the latest git code. Read the instructions below, then visit our bug tracker to submit your bug report. Please do not submit bugs for third party software.

Required Information

Please be sure to include all of the following information so that we can effectively address your bug:

  • E-mail address : a working email address so the developers can get in touch with you to obtain additional info and notify you when the problem is fixed.
  • ClamAV version and settings : the output from: clamconf -n
  • 3rd party signatures : whether you are using any unofficial signature databases, that is anything other than main.cvd/cld and daily.cvd/cld
  • System details : full specs of your system: i.e. output from: uname -mrsp
  • Library versions : your libc and possibly zlib versions
  • How to reproduce the problem : if the issue is reproducible only when scanning a specific file, attach it to the message. Don’t forget to encrypt it or you may cause damage to the mail servers between you and us! E.g.: zip -P virus -e file.ext.The content of the file will be kept confidential.

Large Files

If the file is too big to mail it, you can upload it to a password protected website and send us the URL and the credentials to access it.

Backtrace Instructions

Backtrace of clamscan: if possible, please send us the backtrace obtained from gdb, the GNU Project Debugger. Here are step by step instructions which will guide you through the process. Assuming you get something like: $ clamscan --some-options some_file Segmentation fault

  • Have the kernel write a core dump. For bourne-like shells (e.g. bash): $ ulimit -c unlimitedFor C-like shells (e.g. tcsh): limit coredumpsize unlimited
  • Now you should see the core dumped message:$ clamscan --some-options some_fileSegmentation fault (core dumped)Looking at your current working directory should reveal a file named core.
  • Load the core file into gdb:$ gdb -core=core --args clamscan --some-options some_file(gdb). You should now see the gdb prompt.
  • Just use the bt command at the prompt to make gdb print a full backtrace.Copy and paste it into the bug report. You can use the q command to leave gdb.
  • Obtain a Backtrace of clamd:

    Use ps to get the PID of clamd (first number from the left): $ ps -aux (or ps -elf on SysV) clamav 24897 0.0 1.9 38032 10068 ? S Jan13 0:00 clamd

    Attach gdb to the running process: $ gdb /usr/sbin/clamd 24897 Replace 24897 with the pid of clamd and adjust the path of clamd.

    You should now get the gdb prompt, as: (gdb) If you want clamd to continue running (i.e. until a segmentation fault occurs), issue the continue gdb command, and wait for an error, at which point gdb will return to its prompt.


    • bt will give a backtrace for the current thread.
    • info threads will tell you how many threads there are.
    • thread n will change to the specified thread, after which you can use the bt command again to get it’s backtrace.

    So, you basically want to use Info threads to get the number of threads and their id numbers; and for each thread do thread id_number; then bt. Exit from gdb with the quit command. Reply y to the question about the program still running.


    Optionally, if you think it can help, the output from strace can be included in the report (not covered here).