CVE-2020-16154

A flaw was found in the way the perl-App-cpanminus performed verification of package signatures stored in CHECKSUMS files. A malicious or compromised CPAN server used by a user, or a man-in-the-middle attacker, could use this flaw to bypass signature verification.

Mitigation

This issue can be mitigated by instructing perl-App-cpanminus to only use trusted CPAN mirrors (www.cpan.org or cpan.metacpan.org) and use HTTPS for communication with CPAN servers. The cpanm command can be configured to use the specific CPAN mirror using the --from command line option by running it as:

  cpanm --from https://www.cpan.org ...  

You can also set environment variable PERL_CPANM_OPT to include this command line option to avoid having to specify the URL for every cpanm invocation:

  export PERL_CPANM_OPT="--from https://www.cpan.org"