Marcus Brinkmann discovered that GnuPG before 2.2.8 improperly handled certain command line parameters. A remote attacker could use this to spoof the output of GnuPG and cause unsigned e-mail to appear signed.
For Debian 8 jessie, these problems have been fixed in version 0.3.6-1+deb8u2.
We recommend that you upgrade your python-gnupg packages.
Further information about Extended LTS security advisories can be found at: https://deb.freexian.com/extended-lts/