CVE-2024-43802

Vim is an improved version of the unix vi text editor. When flushing the
typeahead buffer, Vim moves the current position in the typeahead buffer
but does not check whether there is enough space left in the buffer to
handle the next characters. So this may lead to the tb_off position within
the typebuf variable to point outside of the valid buffer size, which can
then later lead to a heap-buffer overflow in e.g. ins_typebuf(). Therefore,
when flushing the typeahead buffer, check if there is enough space left
before advancing the off position. If not, fall back to flush current
typebuf contents. It’s not quite clear yet, what can lead to this
situation. It seems to happen when error messages occur (which will cause
Vim to flush the typeahead buffer) in comnination with several long
mappgins and so it may eventually move the off position out of a valid
buffer size. Impact is low since it is not easily reproducible and requires
to have several mappings active and run into some error condition. But when
this happens, this will cause a crash. The issue has been fixed as of Vim
patch v9.1.0697. Users are advised to upgrade. There are no known
workarounds for this issue.