GNU ed is a basic line editor. red is a restricted version of ed that does not allow shell command execution.
Alfredo Ortega from Core Security Technologies reported a heap-based buffer overflow in the strip_escapes() function when processing overly long filenames.
A remote attacker could entice a user to process specially crafted commands with ed or red, possibly resulting in the execution of arbitrary code with the privileges of the user running the application.
There is no known workaround at this time.
All GNU ed users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose ">=sys-apps/ed-1.0"