On Wed, 18 Aug 2021 19:20:01 +0200 Matthias Andree <matthias.and...@gmx.de> wrote: > The attached patch should fix the crash. envelope is special in that it > can take the value STRING_DISABLED == (char *)-1 for "no envelope", and > the optmerge() function did not take this into account and tried to > strdup(-1).
Minor detail, this happens in strlen(-1). This is a regression that happened in 6.4.3 release (or 6.4.3-beta1, to be precise) and affects all 6.4.x versions up to and including 6.4.21.